1
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Nascimento RO, Prado FM, Massafera MP, Di Mascio P, Ronsein GE. Dehydromethionine is a common product of methionine oxidation by singlet molecular oxygen and hypohalous acids. Free Radic Biol Med 2022; 187:17-28. [PMID: 35580773 DOI: 10.1016/j.freeradbiomed.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/29/2022] [Accepted: 05/05/2022] [Indexed: 10/18/2022]
Abstract
Methionine is one of the main targets for biological oxidants. Its reaction with the majority of oxidants generates only methionine sulfoxide. However, when N-terminal methionine reacts with hypohalous acids (HOCl and HOBr) or singlet molecular oxygen (1O2), it can also generate a cyclic product called dehydromethionine (DHM). Previously, DHM was suggested as a biomarker of oxidative stress induced by hypohalous acids. However, DHM can also be generated by 1O2 -oxidation of methionine, and the contribution of this pathway of DHM formation in a context of a site-specific redox imbalance in an organism is unknown. In this work, a through comparison of the reactions of hypohalous acids and 1O2 with methionine, either free or inserted in peptides and proteins was undertaken. In addition, we performed methionine photooxidation in heavy water (H218O) to determine the influence of the pH in the mechanism of DHM formation. We showed that for free methionine, or methionine-containing peptides, the yields of DHM formation in the reactions with 1O2 were close to those achieved by HOBr oxidation, but much higher than the yields obtained with HOCl as the oxidant. This was true for all pH tested (5, 7.4, and 9). Interestingly, for the protein ubiquitin, DHM yields after reaction with 1O2 were higher than those obtained with both hypohalous acids. Our results indicate that 1O2 may also be an important source of DHM in biological systems.
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Affiliation(s)
| | - Fernanda Manso Prado
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Mariana Pereira Massafera
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Paolo Di Mascio
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil.
| | - Graziella Eliza Ronsein
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil.
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2
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Jayme SB, Prado FM, Massafera MP, Ronsein GE, Di Mascio P. Characterization and Quantification of Tryptophan and Tyrosine- Derived Hydroperoxides. Photochem Photobiol 2022; 98:678-686. [PMID: 35363890 DOI: 10.1111/php.13623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 11/28/2022]
Abstract
The reaction of 1 O2 with the amino acids tryptophan and tyrosine, either free or inserted in peptides or proteins, gives rise to hydroperoxides. To understand the impact of these hydroperoxides in complex biological systems, methods allowing their characterization and accurate quantification must be available. In this work, hydroperoxides derived from tryptophan, tyrosine and from peptides containing these amino acids were synthesized by photooxidation, and characterized by high-resolution mass spectrometry. In addition, experiments were carried out to compare two colorimetric methods commonly used for quantification of peroxides, namely the iodometric and the ferric-xylenol orange assays. For the tryptophan hydroperoxide, the quantifications obtained by colorimetric methods were then compared to that obtained by NMR. The results showed that for the ferric-xylenol orange, the stoichiometry between peroxide and Fe3+ ions vary considerably. On the other hand, for the iodometric assay, the stoichiometry peroxide : I3 - ions is always 1:1. However, the kinetics of the reactions of peroxides with I- vary, and the assay must be perfomed in anaerobic conditions. Thus, the iodometric method is more appropriate for precise quantification of a given peroxide. The characterization and accurate quantification of biological peroxides is key to understand the mechanisms involved in redox processes.
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Affiliation(s)
- Stella Boutris Jayme
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Fernanda Manso Prado
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Mariana Pereira Massafera
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Graziella Eliza Ronsein
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
| | - Paolo Di Mascio
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, 05508-000, Brazil
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3
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Nasri Z, Memari S, Wenske S, Clemen R, Martens U, Delcea M, Bekeschus S, Weltmann K, von Woedtke T, Wende K. Singlet-Oxygen-Induced Phospholipase A 2 Inhibition: A Major Role for Interfacial Tryptophan Dioxidation. Chemistry 2021; 27:14702-14710. [PMID: 34375468 PMCID: PMC8596696 DOI: 10.1002/chem.202102306] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Indexed: 11/16/2022]
Abstract
Several studies have revealed that various diseases such as cancer have been associated with elevated phospholipase A2 (PLA2 ) activity. Therefore, the regulation of PLA2 catalytic activity is undoubtedly vital. In this study, effective inactivation of PLA2 due to reactive species produced from cold physical plasma as a source to model oxidative stress is reported. We found singlet oxygen to be the most relevant active agent in PLA2 inhibition. A more detailed analysis of the plasma-treated PLA2 identified tryptophan 128 as a hot spot, rich in double oxidation. The significant dioxidation of this interfacial tryptophan resulted in an N-formylkynurenine product via the oxidative opening of the tryptophan indole ring. Molecular dynamics simulation indicated that the efficient interactions between the tryptophan residue and phospholipids are eliminated following tryptophan dioxidation. As interfacial tryptophan residues are predominantly involved in the attaching of membrane enzymes to the bilayers, tryptophan dioxidation and indole ring opening leads to the loss of essential interactions for enzyme binding and, consequently, enzyme inactivation.
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Affiliation(s)
- Zahra Nasri
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
| | - Seyedali Memari
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
- Institute of Anatomy and Cell BiologyUniversity Medicine GreifswaldFriedrich-Loeffler-Straße 23cGreifswald17487Germany
| | - Sebastian Wenske
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
| | - Ramona Clemen
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
| | - Ulrike Martens
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Straße 4Greifswald17489Germany
- Center for Innovation Competence (ZIK) HIKE (Humoral Immune Reactions in Cardiovascular Diseases)University of GreifswaldGreifswaldFleischmannstraße 4217489Germany
| | - Mihaela Delcea
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Straße 4Greifswald17489Germany
- Center for Innovation Competence (ZIK) HIKE (Humoral Immune Reactions in Cardiovascular Diseases)University of GreifswaldGreifswaldFleischmannstraße 4217489Germany
| | - Sander Bekeschus
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
| | - Klaus‐Dieter Weltmann
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
| | - Thomas von Woedtke
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
- Institute for Hygiene and Environmental MedicineUniversity Medicine GreifswaldGreifswaldWalther-Rathenau-Straße 49 A17489Germany
| | - Kristian Wende
- Center for Innovation Competence (ZIK) plasmatisLeibniz Institute for Plasma Science and Technology (INP)Felix-Hausdorff-Straße 217489GreifswaldGermany
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4
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Leone L, D’Alonzo D, Maglio O, Pavone V, Nastri F, Lombardi A. Highly Selective Indole Oxidation Catalyzed by a Mn-Containing Artificial Mini-Enzyme. ACS Catal 2021. [DOI: 10.1021/acscatal.1c01985] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Linda Leone
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, Napoli 80126, Italy
| | - Daniele D’Alonzo
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, Napoli 80126, Italy
| | - Ornella Maglio
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, Napoli 80126, Italy
- Institute of Biostructures and Bioimages—National Research Council, Via Mezzocannone 16, Napoli 80134, Italy
| | - Vincenzo Pavone
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, Napoli 80126, Italy
| | - Flavia Nastri
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, Napoli 80126, Italy
| | - Angela Lombardi
- Department of Chemical Sciences, University of Napoli Federico II, Via Cintia 21, Napoli 80126, Italy
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5
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Gérard V, Galopin C, Ay E, Launay V, Morlet-Savary F, Graff B, Lalevée J. Photostability of l-tryptophan in aqueous solution: Effect of atmosphere and antioxidants addition. Food Chem 2021; 359:129949. [PMID: 33957330 DOI: 10.1016/j.foodchem.2021.129949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/10/2021] [Accepted: 04/21/2021] [Indexed: 10/21/2022]
Abstract
l-Tryptophan (l-Trp) is an amino acid important in nutrition, and mainly provided by food supplements. However, it is known to be unstable under light irradiation, which is an issue for the nutrition and feed industry. In the present study, the photostability of l-Trp was studied in acidic aqueous solutions under air and under an inert atmosphere, N2. The photodegradation was followed using UV-visible and fluorescence spectroscopy after photolysis. Moreover, molecular orbitals and bond dissociation energies calculations, and electron spin resonance spectroscopy were performed. From all these results, a photodegradation occurring through a free radical pathway was suggested. Interestingly, several antioxidants were tested to improve the photostability of l-Trp, especially during irradiation under air, since the l-Trp was evidenced to be much less stable under air than under N2. The results showed that sodium benzoate or EDTA were not efficient, but antioxidants such as chlorogenic acid, ascorbic acid or potassium sorbate improved significantly the photostability of l-Trp in acidic solutions.
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Affiliation(s)
- Violaine Gérard
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Université de Strasbourg, F-67000, France
| | - Christophe Galopin
- PepsiCo Global Beverage Research and Development, 100 East Stevens Avenue, Valhalla, New York 10595, USA
| | - Emel Ay
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Université de Strasbourg, F-67000, France
| | - Valentin Launay
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Université de Strasbourg, F-67000, France
| | - Fabrice Morlet-Savary
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Université de Strasbourg, F-67000, France
| | - Bernadette Graff
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Université de Strasbourg, F-67000, France
| | - Jacques Lalevée
- Université de Haute-Alsace, CNRS, IS2M UMR 7361, F-68100 Mulhouse, France; Université de Strasbourg, F-67000, France.
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6
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Torres F, Sobol A, Greenwald J, Renn A, Morozova O, Yurkovskaya A, Riek R. Molecular features toward high photo-CIDNP hyperpolariztion explored through the oxidocyclization of tryptophan. Phys Chem Chem Phys 2021; 23:6641-6650. [PMID: 33710192 DOI: 10.1039/d0cp06068b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Photo-chemically induced dynamic nuclear polarization (photo-CIDNP) is a promising solution to the inherent lack of sensitivity in NMR spectroscopy. It is particularly interesting in biological systems since it operates in water, at room temperature, and it can be repeated if the bleaching of the system can be controlled. However, the photo-CIDNP signal enhancement is well below those of other hyperpolarization techniques. While DNP, PHIP, and SABRE reach polarization enhancements of 103 to 104-fold, photo-CIDNP enhancement is typically only one order of magnitude for 1H and two orders of magnitude for 13C in the amino-acids tryptophan and tyrosine. Here we report on a photo-oxidation product of tryptophan that is strongly photo-CIDNP active under continuous wave light irradiation. In conjunction with the dye Atto Thio 12, a 1H signal enhancement of 120-fold was observed on a 600 MHz spectrometer, while at 200 MHz the enhancement was 380-fold. These enhancements in signal to noise correspond to a reduction in measurement time of 14 400-fold and 144 400-fold, respectively. The enhancement for 13C is estimated to be over 1200-fold at 600 MHz which corresponds to an impressive measurement time reduction of 1 440 000-fold. This photo-CIDNP active oxidation product of tryptophan has been identified to be 3α-hydroxypyrroloindole. The reasons for its improved signal enhancement compared to tryptophan have been further investigated.
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Affiliation(s)
- Felix Torres
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
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7
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Ramos LD, Prado FM, Stevani CV, Di Mascio P, Bechara EJH. l-Tryptophan Interactions with the Horseradish Peroxidase-Catalyzed Generation of Triplet Acetone. Photochem Photobiol 2021; 97:327-334. [PMID: 33296511 DOI: 10.1111/php.13363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/02/2020] [Indexed: 01/01/2023]
Abstract
Triplet carbonyls generated by chemiexcitation are involved in typical photobiochemical processes in the absence of light. Due to their biradical nature, ultraweak light emission and long lifetime, electronically excited triplet species display typical radical reactions such as isomerization, fragmentation, cycloaddition and hydrogen abstraction. In this paper, we report chemical reactions in a set of amino acid residues induced by the isobutanal/horseradish peroxidase (IBAL/HRP) system, a well-known source of excited triplet acetone (Ac3* ). Accordingly, quenching of Ac3* by tryptophan (Trp) unveiled parallel enzyme damage and inactivation, likely explained by scavenging of IBAL tertiary radical reaction intermediate and Ac3* -derived 2-hydroxy-i-propyl radical. Quenching constants were calculated from Stern-Volmer plots, and the structure of radical adducts was revealed by mass spectrometry. As expected, a concurrent Schiff-type adduct was found to be one of the reaction by-products. These findings draw attention to potential structural and functional changes in enzymes involved in the electronic chemiexcitation of their products.
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Affiliation(s)
- Luiz D Ramos
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Fernanda M Prado
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Cassius V Stevani
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Etelvino J H Bechara
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
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8
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O'Connor RM, Greer A. How Tryptophan Oxidation Arises by "Dark" Photoreactions from Chemiexcited Triplet Acetone. Photochem Photobiol 2021; 97:456-459. [PMID: 33386615 DOI: 10.1111/php.13375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 12/29/2020] [Indexed: 12/31/2022]
Abstract
Dioxetane intermediates readily decompose to chemiluminescent triplet carbonyls, giving rise to what has been paradoxically called photochemistry in the dark. In this issue of Photochemistry and Photobiology, Bechara et al. report on mechanistic advances in such a reaction. With the use of horseradish peroxidase for isobutyraldehyde-derived triplet acetone, light emission from acetone and singlet oxygen can be quenched. The experiments reveal that the reaction depends on oxygen and the amino acid. The analysis reveals that free tryptophan is a target of this form of "carbonyl stress," with the efficient formation of mono-, bi- and tricyclic compounds (N-formylkynurenine, indoline, 1λ2 -indole and 3H-indoles).
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Affiliation(s)
- Ryan M O'Connor
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - Alexander Greer
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY, USA
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9
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Arevalo GE, Cagan DA, Monsour CG, Garcia AC, McCurdy A, Selke M. A Photoprotective Effect by Cation-π-Interaction? Quenching of Singlet Oxygen by an Indole Cation-π Model System. Photochem Photobiol 2020; 96:1200-1207. [PMID: 32472700 DOI: 10.1111/php.13287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/17/2020] [Indexed: 01/18/2023]
Abstract
We investigated the effect of the cation-π interaction on the susceptibility of a tryptophan model system toward interaction with singlet oxygen, that is, type II photooxidation. The model system consists of two indole units linked to a lariat crown ether to measure the total rate of removal of singlet oxygen by the indole units in the presence of sodium cations (i.e. indole units subject to a cation-π interaction) and in the absence of this interaction. We found that the cation-π interaction significantly decreases the total rate of removal of singlet oxygen (kT ) for the model system, that is, (kT = 2.4 ± 0.2) × 108 m-1 s-1 without sodium cation vs (kT = 6.9 ± 0.9) × 107 m-1 s-1 upon complexation of sodium cation to the crown ether. Furthermore, we found that the indole moieties undergo type I photooxidation processes with triplet excited methylene blue; this effect is also inhibited by the cation-π interaction. The chemical rate of reaction of the indole groups with singlet oxygen is also slower upon complexation of sodium cation in our model system, although we were unable to obtain an exact ratio due to differences of the chemical reaction rates of the two indole moieties.
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Affiliation(s)
- Gary E Arevalo
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA
| | - David A Cagan
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA
| | - Charlotte G Monsour
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA
| | - Arman C Garcia
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA
| | - Alison McCurdy
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA
| | - Matthias Selke
- Department of Chemistry and Biochemistry, California State University, Los Angeles, CA, USA
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10
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Prado FM, Scalfo AC, Miyamoto S, Medeiros MHG, Di Mascio P. Generation of Singlet Molecular Oxygen by Lipid Hydroperoxides and Nitronium Ion †. Photochem Photobiol 2020; 96:560-569. [PMID: 32108956 DOI: 10.1111/php.13236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/23/2019] [Indexed: 11/29/2022]
Abstract
Singlet molecular oxygen is a reactive species involved in biological oxidative processes. The major cellular targets of singlet molecular oxygen are unsaturated fatty acids in the membrane, as well as nucleic acids and proteins. The aim of this study was to investigate whether lipids and commercial hydroperoxides generate singlet molecular oxygen, in presence of nitronium and activated nitronium ion. For this purpose, monomol light emitted in the near-infrared region (λ = 1270 nm) was used to monitor singlet molecular oxygen decay in different solvents, with different hydroperoxides and in the presence of azide. Direct measurements of the singlet molecular oxygen spectrum at 1270 nm recorded during the reaction between lipids and commercial hydroperoxides and nitronium ions unequivocally demonstrated the formation of this excited species.
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Affiliation(s)
- Fernanda M Prado
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Alexsandra C Scalfo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Sayuri Miyamoto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Marisa H G Medeiros
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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11
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Schöneich C. Photo-Degradation of Therapeutic Proteins: Mechanistic Aspects. Pharm Res 2020; 37:45. [DOI: 10.1007/s11095-020-2763-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 01/15/2020] [Indexed: 12/11/2022]
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12
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Oliveira MS, Chorociejus G, Angeli JPF, Vila Verde G, Aquino GLB, Ronsein GE, Oliveira MCBD, Barbosa LF, Medeiros MHG, Greer A, Di Mascio P. Heck reaction synthesis of anthracene and naphthalene derivatives as traps and clean chemical sources of singlet molecular oxygen in biological systems. Photochem Photobiol Sci 2020; 19:1590-1602. [DOI: 10.1039/d0pp00153h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our study shows that new anthracene and naphthalene derivatives function as compounds for trapping and chemically generating singlet molecular oxygen [O2(1Δg)], respectively. The syntheses of these derivatives are described, as well as some localization testing in cells.
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Affiliation(s)
| | - Gabriel Chorociejus
- Departamento de Bioquímica
- Instituto de Química
- Universidade de São Paulo
- São Paulo
- Brazil
| | - José Pedro F. Angeli
- Rudolf Virchow Center for Translational Bioimaging
- University of Würzburg
- 97080 Würzburg
- Germany
| | - Giuliana Vila Verde
- Campus Anápolis de Ciências Exatas e Tecnológicas Henrique Santillo
- Universidade Estadual de Goiás
- 75001-970 Anápolis
- Brazil
| | - Gilberto L. B. Aquino
- Campus Anápolis de Ciências Exatas e Tecnológicas Henrique Santillo
- Universidade Estadual de Goiás
- 75001-970 Anápolis
- Brazil
| | - Graziella E. Ronsein
- Departamento de Bioquímica
- Instituto de Química
- Universidade de São Paulo
- São Paulo
- Brazil
| | | | - Livea F. Barbosa
- Departamento de Bioquímica
- Instituto de Química
- Universidade de São Paulo
- São Paulo
- Brazil
| | - Marisa H. G. Medeiros
- Departamento de Bioquímica
- Instituto de Química
- Universidade de São Paulo
- São Paulo
- Brazil
| | - Alexander Greer
- Department of Chemistry
- Brooklyn College
- City University of New York
- Brooklyn
- USA
| | - Paolo Di Mascio
- Departamento de Bioquímica
- Instituto de Química
- Universidade de São Paulo
- São Paulo
- Brazil
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13
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Photo-induced protein oxidation: mechanisms, consequences and medical applications. Essays Biochem 2019; 64:33-44. [DOI: 10.1042/ebc20190044] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 01/10/2023]
Abstract
Abstract
Irradiation from the sun has played a crucial role in the origin and evolution of life on the earth. Due to the presence of ozone in the stratosphere most of the hazardous irradiation is absorbed, nonetheless UVB, UVA, and visible light reach the earth’s surface. The high abundance of proteins in most living organisms, and the presence of chromophores in the side chains of certain amino acids, explain why these macromolecules are principal targets when biological systems are illuminated. Light absorption triggers the formation of excited species that can initiate photo-modification of proteins. The major pathways involve modifications derived from direct irradiation and photo-sensitized reactions. In this review we explored the basic concepts behind these photochemical pathways, with special emphasis on the photosensitized mechanisms (type 1 and type 2) leading to protein oxidation, and how this affects protein structure and functions. Finally, a description of the photochemical reactions involved in some human diseases, and medical applications of protein oxidation are presented.
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14
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Marques EF, Medeiros MHG, Di Mascio P. Singlet oxygen-induced protein aggregation: Lysozyme crosslink formation and nLC-MS/MS characterization. JOURNAL OF MASS SPECTROMETRY : JMS 2019; 54:894-905. [PMID: 31652372 DOI: 10.1002/jms.4448] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Singlet molecular oxygen (1 O2 ) has been associated with a number of physiological processes. Despite the recognized importance of 1 O2 -mediated protein modifications, little is known about the role of this oxidant in crosslink formation and protein aggregation. Thus, using lysozyme as a model, the present study sought to investigate the involvement of 1 O2 in crosslink formation. Lysozyme was photochemically oxidized in the presence of rose bengal or chemically oxidized using [18 O]-labeled 1 O2 released from thermolabile endoperoxides. It was concluded that both 1 O2 generating systems induce lysozyme crosslinking and aggregation. Using SDS-PAGE and nano-scale liquid chromatography coupled to electrospray ionization mass spectrometry, the results clearly demonstrated that 1 O2 is directly involved in the formation of covalent crosslinks involving the amino acids histidine, lysine, and tryptophan.
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Affiliation(s)
- Emerson Finco Marques
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Marisa H G Medeiros
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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15
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Unger N, Ferraro A, Holzgrabe U. Investigation of tryptophan-related yellowing in parenteral amino acid solution: Development of a stability-indicating method and assessment of degradation products in pharmaceutical formulations. J Pharm Biomed Anal 2019; 177:112839. [PMID: 31505430 DOI: 10.1016/j.jpba.2019.112839] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 11/18/2022]
Abstract
Parenteral amino acid solutions containing tryptophan tend to develop a yellow colouration upon storage. Hence, the aim of the present study was to find out whether tryptophan degradation products are the reason for the yellowing. The degree of discolouration and tryptophan degradation was examined by visual examination and UV/Vis measurements with respect to oxygen presence, pH value, and duration of steam sterilization. LC-UV analyses of autoclaved tryptophan solutions indicated eight degradation products, namely R,R/R,S 2-amino-3-(oxoindolin-3-yl)propanoic acid, R,R/R,S 2-amino-3-hydroxy-2-oxoindolin-3-yl)propanoic acids, cis/trans 3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid, N´-formylkynurenine, and kynurenine. The proposed degradation products were confirmed by spiking of synthesized degradation products and LC-UV/MS analyses. The LC-UV analysis method was optimized and validated according to the ICH guideline Q2 (R1). Tryptophan stability in commercially available parenteral amino acid formulations was evaluated over a storing period of 12 months in two common types of primary packaging after autoclave procedure.
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Affiliation(s)
- Nina Unger
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Antonio Ferraro
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ulrike Holzgrabe
- Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.
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16
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Bikaki M, Kuhnert N. Identification of Products from Thermal Degradation of Tryptophan Containing Pentapeptides: Oxidation and Decarboxylation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:7448-7454. [PMID: 31244194 DOI: 10.1021/acs.jafc.9b01056] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this contribution, we investigate the thermal decomposition of four pentapeptides containing a tryptophan moiety. Pentapeptides were heated at 220 °C, and the resulting reaction mixtures were investigated by HPLC coupled to high-resolution mass spectrometry and tandem mass spectrometry. A total of 95 thermal decomposition products could be observed and resolved by chromatography. In detail, we report on the structure assignment of two types of reaction products common to investigated peptides and introduce two decomposition mechanisms. Pentapeptides react with oxygen to produce hydroxyl-tryptophan derivatives. In addition, we observe the C-terminal decarboxylation of two peptides to form N-acyl tryptamine derivatives.
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Affiliation(s)
- Maria Bikaki
- Department of Life Sciences & Chemistry , Jacobs University Bremen , Campus Ring 1 , 28759 Bremen , Germany
| | - Nikolai Kuhnert
- Department of Life Sciences & Chemistry , Jacobs University Bremen , Campus Ring 1 , 28759 Bremen , Germany
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17
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Bilkis I, Silman I, Weiner L. Generation of Reactive Oxygen Species by Photosensitizers and their Modes of Action on Proteins. Curr Med Chem 2019; 25:5528-5539. [PMID: 29303072 DOI: 10.2174/0929867325666180104153848] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/11/2017] [Accepted: 08/11/2017] [Indexed: 12/31/2022]
Abstract
In this review, we first survey the mechanisms underlying the chemical modification of amino acid residues in proteins by singlet oxygen elicited by photosensitizers. Singlet oxygen has the capacity to cause widespread chemical damage to cellular proteins. Its use in photodynamic therapy of tumors thus requires the development of methodologies for specific addressing of the photosensitizer to malignant cells while sparing normal tissue. We describe three targeting paradigms for achieving this objective. The first involves the use of a photosensitizer with a high affinity for its target protein; in this case, the photosensitizer is methylene blue for acetylcholinesterase. The second paradigm involves the use of the hydrophobic photosensitizer hypericin, which has the capacity to interact selectively with partially unfolded forms of proteins, including nascent species in rapidly dividing or virus-infected and cancer cells, acting preferentially at membrane interfaces. In this case, partially unfolded molten globule species of acetylcholinesterase serve as the model system. In the third paradigm, the photodynamic approach takes advantage of a general approach in 'state-of-the-art' chemotherapy, by coupling the photosensitizer emodin to a specific peptide hormone, GnRH, which recognizes malignant cells via specific GnRH receptors on their surface.
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Affiliation(s)
- Itzhak Bilkis
- Robert Smith Faculty of Agriculture, Food & Environment, Hebrew University, Rehovot 76 100, Israel
| | - Israel Silman
- Weizmann Institute of Science, Rehovot, 76 100, Israel
| | - Lev Weiner
- Weizmann Institute of Science, Rehovot, 76 100, Israel
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18
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Di Mascio P, Martinez GR, Miyamoto S, Ronsein GE, Medeiros MHG, Cadet J. Singlet Molecular Oxygen Reactions with Nucleic Acids, Lipids, and Proteins. Chem Rev 2019; 119:2043-2086. [DOI: 10.1021/acs.chemrev.8b00554] [Citation(s) in RCA: 253] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05508-000, São Paulo, SP Brazil
| | - Glaucia R. Martinez
- Departamento de Bioquímica e Biologia Molecular, Setor de Ciências Biológicas, Universidade Federal do Paraná, 81531-990 Curitiba, PR, Brazil
| | - Sayuri Miyamoto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05508-000, São Paulo, SP Brazil
| | - Graziella E. Ronsein
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05508-000, São Paulo, SP Brazil
| | - Marisa H. G. Medeiros
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05508-000, São Paulo, SP Brazil
| | - Jean Cadet
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, J1H 5N4 Québec, Canada
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19
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Silva E, Barrias P, Fuentes-Lemus E, Tirapegui C, Aspee A, Carroll L, Davies MJ, López-Alarcón C. Riboflavin-induced Type 1 photo-oxidation of tryptophan using a high intensity 365 nm light emitting diode. Free Radic Biol Med 2019; 131:133-143. [PMID: 30502456 DOI: 10.1016/j.freeradbiomed.2018.11.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/03/2018] [Accepted: 11/21/2018] [Indexed: 10/27/2022]
Abstract
The mechanism of photo-oxidation of tryptophan (Trp) sensitized by riboflavin (RF) was examined employing high concentrations of Trp and RF, with a high intensity 365 nm light emitting diode (LED) source under N2, 20% and 100% O2 atmospheres. Dimerization of Trp was a major pathway under the N2 atmosphere, though this occurred with a low yield (DφTrp = 5.9 × 10-3), probably as a result of extensive back electron transfer reactions between RF•- and Trp(H)•+. The presence of O2 decreased the extent of this back electron transfer reaction, and the extent of Trp dimerization. This difference is attributed to the formation of O2•- (generated via electron transfer from RF•- to O2) which reacts rapidly with Trp• leading to extensive consumption of the parent amino acid and formation of peroxides and multiple other oxygenated products (N-formylkynurenine, alcohols, diols) of Trp, as detected by LC-MS. Thus, it appears that the first step of the Type 1 mechanism of Trp photo-oxidation, induced by this high intensity 365 nm light source, is an electron transfer reaction between the amino acid and 3RF, with the presence of O2 modulating the subsequent reactions and the products formed, as a result of O2•- formation. These data have potential biological significance as LED systems and RF-based treatments have been proposed for the treatment of pathological myopia and keratitis.
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Affiliation(s)
- Eduardo Silva
- Pontificia Universidad Católica de Chile, Facultad de Química, Departamento de Química Física, Santiago, Chile.
| | - Pablo Barrias
- Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Ciencias de los Materiales, Santiago, Chile
| | - Eduardo Fuentes-Lemus
- Pontificia Universidad Católica de Chile, Facultad de Química, Departamento de Química Física, Santiago, Chile
| | - Cristian Tirapegui
- Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Ciencias de los Materiales, Santiago, Chile
| | - Alexis Aspee
- Universidad de Santiago de Chile, Facultad de Química y Biología, Departamento de Ciencias de los Materiales, Santiago, Chile
| | - Luke Carroll
- University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark
| | - Michael J Davies
- University of Copenhagen, Department of Biomedical Sciences, Copenhagen, Denmark
| | - Camilo López-Alarcón
- Pontificia Universidad Católica de Chile, Facultad de Química, Departamento de Química Física, Santiago, Chile.
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20
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Fuentes-Lemus E, Silva E, Barrias P, Aspee A, Escobar E, Lorentzen LG, Carroll L, Leinisch F, Davies MJ, López-Alarcón C. Aggregation of α- and β- caseins induced by peroxyl radicals involves secondary reactions of carbonyl compounds as well as di-tyrosine and di-tryptophan formation. Free Radic Biol Med 2018; 124:176-188. [PMID: 29885785 DOI: 10.1016/j.freeradbiomed.2018.06.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/27/2018] [Accepted: 06/05/2018] [Indexed: 01/21/2023]
Abstract
The present work examined the role of Tyr and Trp in oxidative modifications of caseins, the most abundant milk proteins, induced by peroxyl radicals (ROO•). We hypothesized that the selectivity of ROO• and the high flexibility of caseins (implying a high exposure of Tyr and Trp residues) would favor radical-radical reactions, and di-tyrosine (di-Tyr) and di-tryptophan (di-Trp) formation. Solutions of α- and β-caseins were exposed to ROO• from thermolysis and photolysis of AAPH (2,2'-azobis(2-methylpropionamidine)dihydrochloride). Oxidative modifications were examined using electrophoresis, western blotting, fluorescence, and chromatographic methodologies with diode array, fluorescence and mass detection. Exposure of caseins to AAPH at 37 °C gave fragmentation, cross-linking and protein aggregation. Amino acid analysis showed consumption of Trp, Tyr, Met, His and Lys residues. Quantification of Trp and Tyr products, showed low levels of di-Tyr and di-Trp, together with an accumulation of carbonyls indicating that casein aggregation is, at least partly, associated with secondary reactions between carbonyls and Lys and His residues. AAPH photolysis, which generates a high flux of free radicals increased the extent of formation of di-Tyr in both model peptides and α- and β- caseins; di-Trp was only detected in peptides and α-casein. Thus, in spite of the high flexibility of caseins, which would be expected to favor radical-radical reactions, the low flux of ROO• generated during AAPH thermolysis disfavours the formation of dimeric radical-radical cross-links such as di-Tyr and di-Trp, instead favoring other O2-dependent crosslinking pathways such as those involving secondary reactions of initial carbonyl products.
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Affiliation(s)
- Eduardo Fuentes-Lemus
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Eduardo Silva
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo Barrias
- Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago, Chile
| | - Alexis Aspee
- Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago, Chile
| | - Elizabeth Escobar
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Lasse G Lorentzen
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Luke Carroll
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Fabian Leinisch
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - Camilo López-Alarcón
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile.
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21
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Carroll L, Pattison DI, Davies JB, Anderson RF, Lopez-Alarcon C, Davies MJ. Superoxide radicals react with peptide-derived tryptophan radicals with very high rate constants to give hydroperoxides as major products. Free Radic Biol Med 2018; 118:126-136. [PMID: 29496618 DOI: 10.1016/j.freeradbiomed.2018.02.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 11/23/2022]
Abstract
Oxidative damage is a common process in many biological systems and proteins are major targets for damage due to their high abundance and very high rate constants for reaction with many oxidants (both radicals and two-electron species). Tryptophan (Trp) residues on peptides and proteins are a major sink for a large range of biological oxidants as these side-chains have low radical reduction potentials. The resulting Trp-derived indolyl radicals (Trp•) have long lifetimes in some circumstances due to their delocalized structures, and undergo only slow reaction with molecular oxygen, unlike most other biological radicals. In contrast, we have shown previously that Trp• undergo rapid dimerization. In the current study, we show that Trp• also undergo very fast reaction with superoxide radicals, O2•-, with k 1-2 × 109 M-1 s-1. These values do not alter dramatically with peptide structure, but the values of k correlate with overall peptide positive charge, consistent with positive electrostatic interactions. These reactions compete favourably with Trp• dimerization and O2 addition, indicating that this may be a major fate in some circumstances. The Trp• + O2•- reactions occur primarily by addition, rather than electron transfer, with this resulting in high yields of Trp-derived hydroperoxides. Subsequent degradation of these species, both stimulated and native decay, gives rise to N-formylkynurenine, kynurenine, alcohols and diols. These data indicate that reaction of O2•- with Trp• should be considered as a major pathway to Trp degradation on peptides and proteins subjected to oxidative damage.
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Affiliation(s)
- Luke Carroll
- The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia; Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark
| | - David I Pattison
- The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia
| | - Justin B Davies
- Australian Nuclear Science and Technology Organisation, Lucas Heights, Australia
| | - Robert F Anderson
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand
| | - Camilo Lopez-Alarcon
- Departmento de Quimica Fisica, Facultad de Quimica, Pontificia Universidad Catolica de Chile, Chile
| | - Michael J Davies
- The Heart Research Institute, Sydney, Australia; Sydney Medical School, University of Sydney, Australia; Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Denmark.
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22
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Sormacheva ED, Sherin PS, Tsentalovich YP. Dimerization and oxidation of tryptophan in UV-A photolysis sensitized by kynurenic acid. Free Radic Biol Med 2017; 113:372-384. [PMID: 29024806 DOI: 10.1016/j.freeradbiomed.2017.10.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 11/24/2022]
Abstract
Photoinduced generation of radicals in the eye lens may play an important role in the modification of proteins leading to their coloration, aggregation, and insolubilization. The radicals can be formed via the reactions of photoexcited endogenous chromophores of the human lens with lens proteins, in particular with tryptophan residues. In the present work we studied the reactions induced by UV-A (315-400nm) light between kynurenic acid (KNA), an effective photosensitizer present in the human lens, and N-acetyl-L-tryptophan (NTrpH) under aerobic and anaerobic conditions. Our results show that the reaction mechanism strongly depends on the presence of oxygen in solution. Under aerobic conditions, the generation of singlet oxygen is the major channel of the effective NTrpH oxidation. In argon-bubbled solutions, the quenching of triplet KNA by NTrpH results in the formation of KNA•- and NTrp• radicals. Under laser pulse irradiation, when the radical concentration is high, the main pathway of the radical decay is the back electron transfer with the restoration of initial reagents. Other reactions include (i) the radical combination yielding NTrp dimers and (ii) the oxygen atom transfer from KNA•- to NTrp• with the formation of oxidized NTrp species and deoxygenated KNA products. In continuous-wave photolysis, even trace amounts of molecular oxygen are sufficient to oxidize the majority of KNA•- radicals with the rate constant of (2.0 ± 0.2) × 109M-1s-1, leading to the restoration of KNA and the formation of superoxide radical O2•-. The latter reacts with NTrp• via either the radical combination to form oxidized NTrp (minor pathway), or the electron transfer to restore NTrpH in the ground state (major pathway). As the result, the quantum yields of the starting compound decomposition under continuous-wave anaerobic photolysis are rather low: 1.6% for NTrpH and 0.02% for KNA. The photolysis of KNA with alpha-crystallin yields the same deoxygenated KNA products as the photolysis of KNA with NTrpH, indicating the similarity of the photolysis mechanisms. Thus, inside the eye lens KNA can sensitize both protein photooxidation and protein covalent cross-linking with the minor self-degradation. This may play an important role in the lens protein modifications during the normal aging and cataract development.
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Affiliation(s)
- Ekaterina D Sormacheva
- International Tomography Center SB RAS, Institutskaya str. 3A, 630090 Novosibisrk, Russia
| | - Peter S Sherin
- International Tomography Center SB RAS, Institutskaya str. 3A, 630090 Novosibisrk, Russia; Novosibirsk State University, Pirogova str. 2, 630090 Novosibisrk, Russia.
| | - Yuri P Tsentalovich
- International Tomography Center SB RAS, Institutskaya str. 3A, 630090 Novosibisrk, Russia; Novosibirsk State University, Pirogova str. 2, 630090 Novosibisrk, Russia
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23
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Characterization of N-Acetyl-Tryptophan Degradation in Protein Therapeutic Formulations. J Pharm Sci 2017; 106:3499-3506. [DOI: 10.1016/j.xphs.2017.08.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/31/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
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24
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Marques EF, Medeiros MHG, Di Mascio P. Lysozyme oxidation by singlet molecular oxygen: Peptide characterization using [ 18 O]-labeling oxygen and nLC-MS/MS. JOURNAL OF MASS SPECTROMETRY : JMS 2017; 52:739-751. [PMID: 28801970 DOI: 10.1002/jms.3983] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/24/2017] [Accepted: 08/07/2017] [Indexed: 06/07/2023]
Abstract
Singlet molecular oxygen (1 O2 ) is generated in biological systems and reacts with different biomolecules. Proteins are a major target for 1 O2 , and His, Tyr, Met, Cys, and Trp are oxidized at physiological pH. In the present study, the modification of lysozyme protein by 1 O2 was investigated using mass spectrometry approaches. The experimental findings showed methionine, histidine, and tryptophan oxidation. The experiments were achieved using [18 O]-labeled 1 O2 released from thermolabile endoperoxides in association with nano-scale liquid chromatography coupled to electrospray ionization mass spectrometry. The structural characterization by nLC-MS/MS of the amino acids in the tryptic peptides of the proteins showed addition of [18 O]-labeling atoms in different amino acids.
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Affiliation(s)
- Emerson Finco Marques
- Departamento de Bioquímica and Departamento de Química Fundamental Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Marisa H G Medeiros
- Departamento de Bioquímica and Departamento de Química Fundamental Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Paolo Di Mascio
- Departamento de Bioquímica and Departamento de Química Fundamental Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
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25
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Leinisch F, Mariotti M, Rykaer M, Lopez-Alarcon C, Hägglund P, Davies MJ. Peroxyl radical- and photo-oxidation of glucose 6-phosphate dehydrogenase generates cross-links and functional changes via oxidation of tyrosine and tryptophan residues. Free Radic Biol Med 2017; 112:240-252. [PMID: 28756310 DOI: 10.1016/j.freeradbiomed.2017.07.025] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/11/2017] [Accepted: 07/25/2017] [Indexed: 02/05/2023]
Abstract
Protein oxidation is a frequent event as a result of the high abundance of proteins in biological samples and the multiple processes that generate oxidants. The reactions that occur are complex and poorly understood, but can generate major structural and functional changes on proteins. Current data indicate that pathophysiological processes and multiple human diseases are associated with the accumulation of damaged proteins. In this study we investigated the mechanisms and consequences of exposure of the key metabolic enzyme glucose-6-phosphate dehydrogenase (G6PDH) to peroxyl radicals (ROO•) and singlet oxygen (1O2), with particular emphasis on the role of Trp and Tyr residues in protein cross-linking and fragmentation. Cross-links and high molecular mass aggregates were detected by SDS-PAGE and Western blotting using specific antibodies. Amino acid analysis has provided evidence for Trp and Tyr consumption and formation of oxygenated products (diols, peroxides, N-formylkynurenine, kynurenine) from Trp, and di-tyrosine (from Tyr). Mass spectrometric data obtained after trypsin-digestion in the presence of H216O and H218O, has allowed the mapping of specific cross-linked residues and their locations. These data indicate that specific Tyr-Trp and di-Tyr cross-links are formed from residues that are proximal and surface-accessible, and that the extent of Trp oxidation varies markedly between sites. Limited modification at other residues is also detected. These data indicate that Trp and Tyr residues are readily modified by ROO• and 1O2 with this giving products that impact significantly on protein structure and function. The formation of such cross-links may help rationalize the accumulation of damaged proteins in vivo.
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Affiliation(s)
- Fabian Leinisch
- Dept. of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Michele Mariotti
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Martin Rykaer
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Camilo Lopez-Alarcon
- Departamento de Química Física, Facultad de Química, Pontificia Universidad Catolica de Chile, Avda. Vicuña Mackenna 4860, Santiago, Chile
| | - Per Hägglund
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Michael J Davies
- Dept. of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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26
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Schöneich C. Novel chemical degradation pathways of proteins mediated by tryptophan oxidation: tryptophan side chain fragmentation. J Pharm Pharmacol 2017; 70:655-665. [DOI: 10.1111/jphp.12688] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 12/11/2016] [Indexed: 01/04/2023]
Abstract
Abstract
Objectives
This minireview focuses on novel degradation pathways of proteins in solution via intermediary tryptophan (Trp) radical cations, which are generated via photo-induced electron transfer to suitable acceptors such as disulfide bonds.
Methods
Gas-phase mass spectrometry studies had indicated the potential for Trp radical cations to fragment via release of 3-methylene-3H-indol-1-ium from the side chain. HPLC-MS/MS analysis demonstrates that analogous fragmentation reactions occur during the exposure of peptides and proteins to light or accelerated stability testing.
Key findings
The light exposure of selected peptides and monoclonal antibodies leads to the conversion of Trp to glycine (Gly) or glycine hydroperoxide (GlyOOH), where GlyOOH could be reduced to hydroxyglycine, which undergoes subsequent cleavage. Product formation is consistent with Cα–Cβ fragmentation of intermediary Trp radical cations. For the peptide octreotide and specific glycoforms of IgG1 Fc domains, Trp side chain cleavage in aqueous solution is indicated by the formation of 3-methyleneindolenine (3-MEI), which adds to nucleophilic side chains, for example to Lys residues adjacent to the original Trp residues.
Conclusions
Trp side chain cleavage leads to novel reaction products on specific peptide and protein sequences, which may have consequences for potency and immunogenicity.
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Affiliation(s)
- Christian Schöneich
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, KS, USA
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27
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Wood GPF, Sreedhara A, Moore JM, Wang J, Trout BL. Mechanistic Insights into Radical-Mediated Oxidation of Tryptophan from ab Initio Quantum Chemistry Calculations and QM/MM Molecular Dynamics Simulations. J Phys Chem A 2016; 120:2926-39. [DOI: 10.1021/acs.jpca.6b02429] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Geoffrey P. F. Wood
- Department
of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts
Avenue, E19-502b, Cambridge, Massachusetts 02139, United States
| | - Alavattam Sreedhara
- Late
Stage Pharmaceutical Development, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Jamie M. Moore
- Late
Stage Pharmaceutical Development, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | | | - Bernhardt L. Trout
- Department
of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts
Avenue, E19-502b, Cambridge, Massachusetts 02139, United States
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28
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Abstract
Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established.
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Affiliation(s)
- Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Blegdamsvej 3, Copenhagen 2200, Denmark
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29
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Ehrenshaft M, Deterding LJ, Mason RP. Tripping up Trp: Modification of protein tryptophan residues by reactive oxygen species, modes of detection, and biological consequences. Free Radic Biol Med 2015; 89:220-8. [PMID: 26393422 PMCID: PMC4684788 DOI: 10.1016/j.freeradbiomed.2015.08.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 08/07/2015] [Accepted: 08/08/2015] [Indexed: 01/22/2023]
Abstract
Proteins comprise a majority of the dry weight of a cell, rendering them a major target for oxidative modification. Oxidation of proteins can result in significant alterations in protein molecular mass such as breakage of the polypeptide backbone and/or polymerization of monomers into dimers, multimers, and sometimes insoluble aggregates. Protein oxidation can also result in structural changes to amino acid residue side chains, conversions that have only a modest effect on protein size but can have widespread consequences for protein function. There are a wide range of rate constants for amino acid reactivity, with cysteine, methionine, tyrosine, phenylalanine, and tryptophan having the highest rate constants with commonly encountered biological oxidants. Free tryptophan and tryptophan protein residues react at a diffusion-limited rate with hydroxyl radical and also have high rate constants for reactions with singlet oxygen and ozone. Although oxidation of proteins in general and tryptophan residues specifically can have effects detrimental to the health of cells and organisms, some modifications are neutral, whereas others contribute to the function of the protein in question or may act as a signal that damaged proteins need to be replaced. This review provides a brief overview of the chemical mechanisms by which tryptophan residues become oxidized, presents both the strengths and the weaknesses of some of the techniques used to detect these oxidative interactions, and discusses selected examples of the biological consequences of tryptophan oxidation in proteins from animals, plants, and microbes.
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Affiliation(s)
- Marilyn Ehrenshaft
- Immunity, Inflammation and Disease Laboratory and National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Ronald P Mason
- Immunity, Inflammation and Disease Laboratory and National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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30
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Paviani V, Queiroz RF, Marques EF, Di Mascio P, Augusto O. Production of lysozyme and lysozyme-superoxide dismutase dimers bound by a ditryptophan cross-link in carbonate radical-treated lysozyme. Free Radic Biol Med 2015. [PMID: 26197052 DOI: 10.1016/j.freeradbiomed.2015.07.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Despite extensive investigation of the irreversible oxidations undergone by proteins in vitro and in vivo, the products formed from the oxidation of Trp residues remain incompletely understood. Recently, we characterized a ditryptophan cross-link produced by the recombination of hSOD1-tryptophanyl radicals generated from attack of the carbonate radical produced during the bicarbonate-dependent peroxidase activity of the enzyme. Here, we examine whether the ditryptophan cross-link is produced by the attack of the carbonate radical on proteins other than hSOD1. To this end, we treated hen egg white lysozyme with photolytically and enzymatically generated carbonate radical. The radical yields were estimated and the lysozyme modifications were analyzed by SDS-PAGE, western blot, enzymatic activity and MS/MS analysis. Lysozyme oxidation by both systems resulted in its inactivation and dimerization. Lysozyme treated with the photolytic system presented monomers oxidized to hydroxy-tryptophan at Trp(28) and Trp(123) and N-formylkynurenine at Trp(28), Trp(62) and Trp(123). Lysozyme treated with the enzymatic system rendered monomers oxidized to N-formylkynurenine at Trp(28). The dimers were characterized as lysozyme-Trp(28)-Trp(28)-lysozyme and lysozyme-Trp(28)-Trp(32)-hSOD1. The results further demonstrate that the carbonate radical is prone to causing biomolecule cross-linking and hence, may be a relevant player in pathological mechanisms. The possibility of exploring the formation of ditryptophan cross-links as a carbonate radical biomarker is discussed.
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Affiliation(s)
- Verônica Paviani
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo
| | - Raphael F Queiroz
- Departamento de Química e Exatas, Universidade Estadual do Sudoeste da Bahia
| | - Emerson F Marques
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo
| | - Paolo Di Mascio
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo
| | - Ohara Augusto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo.
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31
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Onyango AN. Alternatives to the 'water oxidation pathway' of biological ozone formation. J Chem Biol 2015; 9:1-8. [PMID: 26855676 DOI: 10.1007/s12154-015-0140-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 06/05/2015] [Indexed: 12/31/2022] Open
Abstract
Recent studies have shown that ozone (O3) is endogenously generated in living tissues, where it makes both positive and negative physiological contributions. A pathway for the formation of both O3 and hydrogen peroxide (H2O2) was previously proposed, beginning with the antibody or amino acid-catalyzed oxidation of water by singlet oxygen ((1)O2) to form hydrogen trioxide (H2O3) as a key intermediate. A key pillar of this hypothesis is that some of the H2O2 molecules incorporate water-derived oxygen atoms. However, H2O3 decomposes extremely readily in water to form (1)O2 and water, rather than O3 and H2O2. This article highlights key literature indicating that the oxidation of organic molecules such as the amino acids methionine, tryptophan, histidine, and cysteine by (1)O2 is involved in ozone formation. Based on this, an alternative hypothesis for ozone formation is developed involving a further reaction of singlet oxygen with various oxidized organic intermediates. H2O2 having water-derived oxygen atoms is subsequently formed during ozone decomposition in water by known reactions.
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Affiliation(s)
- Arnold N Onyango
- Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology, P. O. Box 62000, 00200 Nairobi, Kenya
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32
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Storkey C, Pattison DI, Koehler JA, Gaspard DS, Evans JC, Hagestuen ED, Davies MJ. Prevention of degradation of the natural high potency sweetener (2R,4R)-monatin in mock beverage solutions. Food Chem 2015; 173:645-51. [PMID: 25466071 DOI: 10.1016/j.foodchem.2014.10.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/30/2014] [Accepted: 10/13/2014] [Indexed: 11/16/2022]
Abstract
Exposure of the naturally-occurring sweetener monatin to light and metal ions results in loss of both parent monatin and total indole (monatin plus monatin lactone/lactam) in mock beverage solutions, with an accompanying decrease in sweetness. In this study potential protective strategies to prevent degradation were investigated. Metal ion chelating resin, or the chelators EDTA and desferrioxamine decreased monatin and indole loss for solutions kept either in darkness or exposed to light. Tannic acid and Chinese bayberry extract both afforded protection, but this did not arise from a light filtering effect. Plastics with defined absorbance characteristics provided protection with this being wavelength dependent; yellow transparent PET plastic was most effective. The contribution of these interventions (metal ion removal/binding; antioxidant; light absorption) was additive, with combinations providing the greatest protective effect against monatin and indole loss. These results indicate that it is possible to minimise monatin degradation by appropriate choices of treatments, additives and container.
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Affiliation(s)
- Corin Storkey
- The Heart Research Institute, 7 Eliza Street, Newtown, NSW 2042, Australia; Faculty of Medicine, University of Sydney, Sydney, NSW 2006, Australia
| | - David I Pattison
- The Heart Research Institute, 7 Eliza Street, Newtown, NSW 2042, Australia; Faculty of Medicine, University of Sydney, Sydney, NSW 2006, Australia
| | - Jamie A Koehler
- Cargill, Inc., 15407 McGinty Road West, Wayzata, MN 55391, USA
| | - Dan S Gaspard
- Cargill, Inc., 15407 McGinty Road West, Wayzata, MN 55391, USA
| | - Jeff C Evans
- Cargill, Inc., 15407 McGinty Road West, Wayzata, MN 55391, USA
| | | | - Michael J Davies
- The Heart Research Institute, 7 Eliza Street, Newtown, NSW 2042, Australia; Faculty of Medicine, University of Sydney, Sydney, NSW 2006, Australia.
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Plowman JE, Deb-Choudhury S, Grosvenor AJ, Dyer JM. Protein oxidation: identification and utilisation of molecular markers to differentiate singlet oxygen and hydroxyl radical-mediated oxidative pathways. Photochem Photobiol Sci 2014; 12:1960-7. [PMID: 24057301 DOI: 10.1039/c3pp50182e] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of reactive oxidation species (ROS) on tryptophan or tyrosine was investigated by qualitatively determining the major detectable oxidation products generated by hydroxyl radicals, produced by the Fenton process, or singlet oxygen, generated by exposure to green light in the presence of Rose Bengal, on these photosensitive amino acids in synthetic pentapeptides. Based on mass spectrometric analysis it would appear that the hydroxyl radical favours a pathway leading to the formation of tryptophandione-based products from tryptophan. In contrast singlet oxygen attack appears to favour the formation of kynurenine-type products from tryptophan. Specific oxidative products observed proteomically are therefore potentially able to discriminate between predominant ROS-mediated pathways. To validate these findings, a keratin-enriched extract was exposed to UVB light under aqueous conditions. The observation of the conversion of tryptophan to hydroxytryptophan in marker peptides, and the absence of singlet-oxygen specific modifications, suggested that under these conditions oxidative degradation occurred primarily via hydroxyl radical attack. These observations provide the first direct proteomic evidence of the dominant photodegradation pathways in wet wool.
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Affiliation(s)
- Jeffrey E Plowman
- Food & Bio-Based Products, AgResearch, Lincoln Research Centre, Christchurch, New Zealand.
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34
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Yu P, Hegeman AD, Cohen JD. A facile means for the identification of indolic compounds from plant tissues. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:1065-75. [PMID: 25040570 DOI: 10.1111/tpj.12607] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/08/2014] [Accepted: 07/01/2014] [Indexed: 05/11/2023]
Abstract
The bulk of indole-3-acetic acid (IAA) in plants is found in the form of conjugated molecules, yet past research on identifying these compounds has largely relied on methods that were both laborious and inefficient. Using recent advances in analytical instrumentation, we have developed a simple yet powerful liquid chromatography-mass spectrometry (LC-MS)-based method for the facile characterization of the small IAA conjugate profile of plants. The method uses the well-known quinolinium ion (m/z 130.0651) generated in MS processes as a signature with high mass accuracy that can be used to screen plant extracts for indolic compounds, including IAA conjugates. We reinvestigated Glycine max (soybean) for its indoles and found indole-3-acetyl-trytophan (IA-Trp) in addition to the already known indole-3-acetyl-aspartic acid (IA-Asp) and indole-3-acetyl-glutamic acid (IA-Glu) conjugates. Surprisingly, several organic acid conjugates of tryptophan were also discovered, many of which have not been reported in planta before. These compounds may have important physiological roles in tryptophan metabolism, which in turn can affect human nutrition. We also demonstrated the general applicability of this method by identifying indolic compounds in different plant tissues of diverse phylogenetic origins. It involves minimal sample preparation but can work in conjunction with sample enrichment techniques. This method enables quick screening of IAA conjugates in both previously characterized as well as uncharacterized species, and facilitates the identification of indolic compounds in general.
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Affiliation(s)
- Peng Yu
- Plant Biological Sciences Graduate Program, Department of Horticultural Science, Microbial and Plant Genomics Institute, University of Minnesota, 1970 Folwell Avenue, Saint Paul, MN, 55108, USA
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35
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Bonifay V, Barrett TJ, Pattison DI, Davies MJ, Hawkins CL, Ashby MT. Tryptophan oxidation in proteins exposed to thiocyanate-derived oxidants. Arch Biochem Biophys 2014; 564:1-11. [PMID: 25172223 DOI: 10.1016/j.abb.2014.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 08/02/2014] [Accepted: 08/18/2014] [Indexed: 01/15/2023]
Abstract
Human defensive peroxidases, including lactoperoxidase (LPO) and myeloperoxidase (MPO), are capable of catalyzing the oxidation of halides (X(-)) by H2O2 to give hypohalous acids (HOX) for the purpose of cellular defense. Substrate selectivity depends upon the relative abundance of the halides, but the pseudo-halide thiocyanate (SCN(-)) is a major substrate, and sometimes the exclusive substrate, of all defensive peroxidases in most physiologic fluids. The resulting hypothiocyanous acid (HOSCN) has been implicated in cellular damage via thiol oxidation. While thiols are believed to be the primary target of HOSCN in vivo, Trp residues have also been implicated as targets for HOSCN. However, the mechanism involved in HOSCN-mediated Trp oxidation was not established. Trp residues in proteins appeared to be susceptible to oxidation by HOSCN, whereas free Trp and Trp residues in small peptides were found to be unreactive. We show that HOSCN-induced Trp oxidation is dependent on pH, with oxidation of free Trp, and Trp-containing peptides observed when the pH is below 2. These conditions mimic those employed previously to precipitate proteins after treatment with HOSCN, which accounts for the discrepancy in the results reported for proteins versus free Trp and small peptides. The reactant in these cases may be thiocyanogen ((SCN)2), which is produced by comproportionation of HOSCN and SCN(-) at low pH. Reaction of thiocyanate-derived oxidants with protein Trp residues at low pH results in the formation of a number of oxidation products, including mono- and di-oxygenated derivatives, which are also formed with other hypohalous acids. Our data suggest that significant modification of Trp by HOSCN in vivo is likely to have limited biological relevance.
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Affiliation(s)
- Vincent Bonifay
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA
| | - Tessa J Barrett
- Heart Research Institute, 7 Eliza St, Newtown, NSW 2042, Australia; Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
| | - David I Pattison
- Heart Research Institute, 7 Eliza St, Newtown, NSW 2042, Australia; Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
| | - Michael J Davies
- Heart Research Institute, 7 Eliza St, Newtown, NSW 2042, Australia; Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
| | - Clare L Hawkins
- Heart Research Institute, 7 Eliza St, Newtown, NSW 2042, Australia; Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
| | - Michael T Ashby
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK 73019, USA.
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36
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Villaverde A, Morcuende D, Estévez M. Effect of Curing Agents on the Oxidative and Nitrosative Damage to Meat Proteins during Processing of Fermented Sausages. J Food Sci 2014; 79:C1331-42. [DOI: 10.1111/1750-3841.12481] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 04/07/2014] [Indexed: 11/26/2022]
Affiliation(s)
- A. Villaverde
- Authors are with TECAL research group; Animal Production and Food Science; Univ. of Extremadura; 10003 Cáceres Spain
| | - D. Morcuende
- Authors are with TECAL research group; Animal Production and Food Science; Univ. of Extremadura; 10003 Cáceres Spain
| | - M. Estévez
- Authors are with TECAL research group; Animal Production and Food Science; Univ. of Extremadura; 10003 Cáceres Spain
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37
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Storkey C, Pattison DI, Gaspard DS, Hagestuen ED, Davies MJ. Mechanisms of degradation of the natural high-potency sweetener (2R,4R)-monatin in mock beverage solutions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:3476-3487. [PMID: 24628536 DOI: 10.1021/jf404198w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The sodium, potassium, or mixed sodium/potassium salt of the naturally occurring high-potency sweetener (2R,4R)-monatin, also known by the common name arruva, degrades over time in model beverage solutions in the presence of light. By use of UHPLC, LC-MS/MS, and peroxide assays, it has been demonstrated that degradation is accelerated by UV/visible light and the presence of trace metal ions. Data are presented that are consistent with a role for singlet oxygen (¹O₂), free radicals, and peroxides (both H₂O₂ and organic peroxides) in monatin oxidation. Separation of degradation products by UHPLC/HPLC or LC-MS/MS provided evidence for the formation of hydroxylated and peroxide species formed on the indole ring (mass increases 16 and 32, respectively) as well as multiple ring and side-chain oxidation and scission products. Model oxidation systems using the photosensitizer Rose Bengal as a source of ¹O₂ support the proposed photodegradation pathways.
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Affiliation(s)
- Corin Storkey
- The Heart Research Institute, 7 Eliza Street, Newtown, New South Wales 2042, Australia
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38
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Wood GPF, Sreedhara A, Moore JM, Trout BL. Reactions of Benzene and 3-Methylpyrrole with the •OH and •OOH Radicals: An Assessment of Contemporary Density Functional Theory Methods. J Phys Chem A 2014; 118:2667-82. [DOI: 10.1021/jp5009708] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Geoffrey P. F. Wood
- Department
of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts
Avenue, E19-502b, Cambridge, Massachusetts 02139, United States
| | - Alavattam Sreedhara
- Late
Stage Pharmaceutical Development, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Jamie M. Moore
- Late
Stage Pharmaceutical Development, Genentech, 1 DNA Way, South San Francisco, California 94080, United States
| | - Bernhardt L. Trout
- Department
of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts
Avenue, E19-502b, Cambridge, Massachusetts 02139, United States
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39
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Geng J, Liu A. Heme-dependent dioxygenases in tryptophan oxidation. Arch Biochem Biophys 2013; 544:18-26. [PMID: 24295960 DOI: 10.1016/j.abb.2013.11.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/19/2013] [Accepted: 11/20/2013] [Indexed: 12/29/2022]
Abstract
L-Tryptophan is an essential amino acid for mammals. It is utilized not only for protein synthesis but also for the biosynthesis of serotonin and melatonin by the serotonin pathway as well as nicotinamide adenine dinucleotide by the kynurenine pathway. Although the kynurenine pathway is responsible for the catabolism of over 90% of l-tryptophan in the mammalian intracellular and extracellular pools, the scientific field was dominated in the last century by studies of the serotonin pathway, due to the physiological significance of the latter's catabolic intermediates and products. However, in the past decade, the focus gradually reversed as the link between the kynurenine pathway and various neurodegenerative disorders and immune diseases is increasingly highlighted. Notably, the first step of this pathway, which is catalyzed by heme-dependent dioxygenases, has been proven to be a potential target for immune regulation and cancer treatment. A thorough understanding of the intriguing chemistry of the heme-dependent dioxygenases may yield insight for the drug discovery of these prevalent illnesses. In this review, we survey enzymatic and mechanistic studies, initially started by Kotake and Masayama over 70 years ago, at the molecular level on the heme-dependent tryptophan dioxygenation reactions.
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Affiliation(s)
- Jiafeng Geng
- Department of Chemistry, Georgia State University, 50 Decatur Street SE, Atlanta, GA 30303, United States
| | - Aimin Liu
- Department of Chemistry, Georgia State University, 50 Decatur Street SE, Atlanta, GA 30303, United States.
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40
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Casbeer EM, Sharma VK, Zajickova Z, Dionysiou DD. Kinetics and mechanism of oxidation of tryptophan by ferrate(VI). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:4572-4580. [PMID: 23517271 DOI: 10.1021/es305283k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Kinetics of the oxidation of tryptophan (Trp) and kynurenine (Kyn), precursors of nitrogenous disinfection byproducts (N-DBP), by ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) were investigated over the acidic to basic pH range. The second-order rate constants decreased with increase in pH, which could be described by the speciation of Fe(VI) and Trp (or Kyn). The trend of pH dependence of rates for Trp (i.e., aromatic α-amino acid) differs from that for glycine (i.e., aliphatic α-amino acid). A nonlinear relationship between transformation of Trp and the added amount of Fe(VI) was found. This suggests that the formed intermediate oxidized products (OPs), identified by LC-PDA and LC-MS techniques, could possibly compete with Trp to react with Fe(VI). N-Formylkynurenine (NFK) at pH 7.0 and 4-hydroxyquinoline (4-OH Q) and kynurenic acid (Kyn-A) at pH 9.0 were the major OPs. Tryptophan radical formation during the reaction was confirmed by the rapid-freeze quench EPR experiments. The oxygen atom transfer from Fe(VI) to NFK was demonstrated by reacting Fe(18)O4(2-) ion with Trp. A proposed mechanism explains the identified OPs at both neutral and alkaline pH. Kinetics and OPs by Fe(VI) were compared with other oxidants (chlorine, ClO2(•), O3, and (•)OH).
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Affiliation(s)
- Erik M Casbeer
- Chemistry Department, Florida Institute of Technology, 150 West University Boulevard, Melbourne, Florida 32901, USA
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41
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Plasma Protein Hydroperoxides During Aging in Humans: Correlation with Paraoxonase 1 (PON1) Arylesterase Activity and Plasma Total Thiols. Arch Med Res 2013; 44:136-41. [DOI: 10.1016/j.arcmed.2013.01.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/18/2013] [Indexed: 11/19/2022]
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42
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Tacal O, Li B, Lockridge O, Schopfer LM. Resistance of human butyrylcholinesterase to methylene blue-catalyzed photoinactivation; mass spectrometry analysis of oxidation products. Photochem Photobiol 2012; 89:336-48. [PMID: 23136924 DOI: 10.1111/php.12016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 10/30/2012] [Indexed: 12/01/2022]
Abstract
Methylene blue, 3, 7-bis(dimethylamino)-phenothiazin-5-ium chloride, is a reversible inhibitor of human butyrylcholinesterase (BChE) in the absence of light. In the presence of light and oxygen, methylene blue promotes irreversible inhibition of human BChE as a function of time, requiring 3 h irradiation to inhibit 95% activity. Inactivation was accompanied by a progressive loss of Coomassie-stained protein bands on native and denaturing polyacrylamide gels, suggesting backbone fragmentation. Aggregation was not detected. MALDI-TOF/TOF mass spectrometry identified oxidized tryptophan (W52, 56, 231, 376, 412, 490, 522), oxidized methionine (M81, 144, 302, 532, 554, 555), oxidized histidine (H214), oxidized proline (P230), oxidized cysteine (C519) and oxidized serine (S215). A 20 min irradiation in the presence of methylene blue resulted in 17% loss of BChE activity, suggesting that BChE is relatively resistant to methylene blue-catalyzed photoinactivation and that therefore this process could be used to sterilize BChE preparations.
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Affiliation(s)
- Ozden Tacal
- Department of Biochemistry, School of Pharmacy, Hacettepe University, Ankara, Turkey
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43
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Utrera M, Estévez M. Analysis of tryptophan oxidation by fluorescence spectroscopy: Effect of metal-catalyzed oxidation and selected phenolic compounds. Food Chem 2012. [DOI: 10.1016/j.foodchem.2012.04.101] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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44
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Abstract
The heme enzyme indoleamine 2,3-dioxygenase (IDO) was found to catalyze the oxidation of indole by H(2)O(2), with generation of 2- and 3-oxoindole as the major products. This reaction occurred in the absence of O(2) and reducing agents and was not inhibited by superoxide dismutase or hydroxyl radical scavengers, although it was strongly inhibited by L-Trp. The stoichiometry of the reaction indicated a one-to-one correspondence for the consumption of indole and H(2)O(2). The (18)O-labeling experiments indicated that the oxygen incorporated into the monooxygenated products was derived almost exclusively from H(2)(18)O(2), suggesting that electron transfer was coupled to the transfer of oxygen from a ferryl intermediate of IDO. These results demonstrate that IDO oxidizes indole by means of a previously unrecognized peroxygenase activity. We conclude that IDO inserts oxygen into indole in a reaction that is mechanistically analogous to the "peroxide shunt" pathway of cytochrome P450.
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45
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Steinmann D, Ji JA, Wang YJ, Schöneich C. Oxidation of human growth hormone by oxygen-centered radicals: formation of Leu-101 hydroperoxide and Tyr-103 oxidation products. Mol Pharm 2012; 9:803-14. [PMID: 22397317 DOI: 10.1021/mp3001028] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human growth hormone (hGH) was exposed to oxygen-centered radicals generated through the thermolysis of AAPH in the presence of dioxygen. Such conditions mimic oxidative processes which protein pharmaceuticals can encounter during formulation in the presence of polysorbates. We detected the oxidation of Met to Met sulfoxide, the formation of protein carbonyls, the oxidation of Tyr to dityrosine and several additional Tyr oxidation products, the conformation-dependent oxidation of Trp, and the site-specific formation of protein hydroperoxides. The sensitivity of Met oxidation correlates with their solvent accessible surface, i.e. the yields of MetSO decreased in the order Met-14 > Met-125 > Met-170. Trp oxidation in native hGH was negligible, but was enhanced through denaturation. Dityrosine formed predominantly intramolecularly but did not contribute significantly to protein cross-linking. Hydroperoxides formed selectively on Leu-101 and were generated specifically by alkoxyl radicals, generated through the decomposition of peroxyl radicals. Tyr-103 was converted into a series of oxidation products characterized by mass shifts of Tyr + 14 Da and Tyr + 16 Da.
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Affiliation(s)
- Daniel Steinmann
- Department of Pharmaceutical Chemistry, University of Kansas , Lawrence, Kansas 66047, USA
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Fredenhagen A, Kittelmann M, Oberer L, Kuhn A, Kühnöl J, Délémonté T, Aichholz R, Wang P, Atadja P, Shultz MD. Biocatalytic synthesis and structure elucidation of cyclized metabolites of the deacetylase inhibitor panobinostat (LBH589). Drug Metab Dispos 2012; 40:1041-50. [PMID: 22344701 DOI: 10.1124/dmd.111.043620] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Panobinostat (LBH589) is a novel pan-deacetylase inhibitor that is currently being evaluated in phase III clinical trials for treatment of Hodgkin's lymphoma and multiple myeloma. Under catalysis of recombinant human CYP3A4 and CYP2D6 coexpressed with human cytochrome P450 reductase in Escherichia coli JM109, five metabolites of panobinostat were produced via whole-cell biotransformation. The structures of the metabolites were elucidated with the spectroscopic methods mass spectrometry (MS) and NMR and revealed an oxidative cyclization of the ethyl-amino group to the methylindole moiety. The MS(2) spectrum of the cyclized metabolite showed a base peak, where the closed ring is reopened and that, taken as sole base for structure proposals, would have lead to wrong conclusions. The metabolites were substantially less potent deacetylase inhibitors than the parent compound.
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Affiliation(s)
- Andreas Fredenhagen
- Global Ciscovery Chemistry, Novartis Institutes for BioMedical Research, WKL-122.P.37, CH-4002 Basel, Switzerland.
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Suryo Rahmanto A, Davies MJ. Catalytic activity of selenomethionine in removing amino acid, peptide, and protein hydroperoxides. Free Radic Biol Med 2011; 51:2288-99. [PMID: 22015433 DOI: 10.1016/j.freeradbiomed.2011.09.027] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 09/23/2011] [Accepted: 09/23/2011] [Indexed: 11/21/2022]
Abstract
Selenium is a critical trace element, with deficiency associated with numerous diseases including cardiovascular disease, diabetes, and cancer. Selenomethionine (SeMet; a selenium analogue of the amino acid methionine, Met) is a major form of organic selenium and an important dietary source of selenium for selenoprotein synthesis in vivo. As selenium compounds can be readily oxidized and reduced, and selenocysteine residues play a critical role in the catalytic activity of the key protective enzymes glutathione peroxidase and thioredoxin reductase, we investigated the ability of SeMet (and its sulfur analogue, Met) to scavenge hydroperoxides present on amino acids, peptides, and proteins, which are key intermediates in protein oxidation. We show that SeMet, but not Met, can remove these species both stoichiometrically and catalytically in the presence of glutathione (GSH) or a thioredoxin reductase (TrxR)/thioredoxin (Trx)/NADPH system. Reaction of the hydroperoxide with SeMet results in selenoxide formation as detected by HPLC. Recycling of the selenoxide back to SeMet occurs rapidly with GSH, TrxR/NADPH, or a complete TrxR/Trx/NADPH reducing system, with this resulting in an enhanced rate of peroxide removal. In the complete TrxR/Trx/NADPH system loss of peroxide is essentially stoichiometric with NADPH consumption, indicative of a highly efficient system. Similar reactions do not occur with Met under these conditions. Studies using murine macrophage-like J774A.1 cells demonstrate a greater peroxide-removing capacity in cells supplemented with SeMet, compared to nonsupplemented controls. Overall, these findings demonstrate that SeMet may play an important role in the catalytic removal of damaging peptide and protein oxidation products.
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Basran J, Efimov I, Chauhan N, Thackray SJ, Krupa JL, Eaton G, Griffith GA, Mowat CG, Handa S, Raven EL. The mechanism of formation of N-formylkynurenine by heme dioxygenases. J Am Chem Soc 2011; 133:16251-7. [PMID: 21892828 PMCID: PMC3210546 DOI: 10.1021/ja207066z] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Indexed: 01/22/2023]
Abstract
Heme dioxygenases catalyze the oxidation of L-tryptophan to N-formylkynurenine (NFK), the first and rate-limiting step in tryptophan catabolism. Although recent progress has been made on early stages in the mechanism, there is currently no experimental data on the mechanism of product (NFK) formation. In this work, we have used mass spectrometry to examine product formation in a number of dioxygenases. In addition to NFK formation (m/z = 237), the data identify a species (m/z = 221) that is consistent with insertion of a single atom of oxygen into the substrate during O(2)-driven turnover. The fragmentation pattern for this m/z = 221 species is consistent with a cyclic amino acetal structure; independent chemical synthesis of the 3a-hydroxypyrroloindole-2-carboxylic acid compound is in agreement with this assignment. Labeling experiments with (18)O(2) confirm the origin of the oxygen atom as arising from O(2)-dependent turnover. These data suggest that the dioxygenases use a ring-opening mechanism during NFK formation, rather than Criegee or dioxetane mechanisms as previously proposed.
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Affiliation(s)
- Jaswir Basran
- Department of Biochemistry, University of Leicester, Lancaster Road, Leicester LE1 9HN, United Kingdom
| | - Igor Efimov
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Nishma Chauhan
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Sarah J. Thackray
- EaStCHEM, School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom
| | - James L. Krupa
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Graham Eaton
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Gerry A. Griffith
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Christopher G. Mowat
- EaStCHEM, School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom
| | - Sandeep Handa
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | - Emma Lloyd Raven
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
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Todorovski T, Fedorova M, Hoffmann R. Mass spectrometric characterization of peptides containing different oxidized tryptophan residues. JOURNAL OF MASS SPECTROMETRY : JMS 2011; 46:1030-1038. [PMID: 22012669 DOI: 10.1002/jms.1984] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The term reactive oxygen species refers to small molecules that can oxidize, for example, nearby proteins, especially cysteine, methionine, tryptophan, and tyrosine residues. Tryptophan oxidation is always irreversible in the cell and can yield several oxidation products, such as 5-hydroxy-tryptophan (5-HTP), oxindolylalanine (Oia), kynurenine (Kyn), and N-formyl-kynurenine (NFK). Because of the severe effects that oxidized tryptophan residues can have on proteins, there is a great need to develop generally applicable and highly sensitive techniques to identify the oxidized residue and the oxidation product. Here, the fragmentation behavior of synthetic peptides corresponding to sequences recently identified in three skeletal muscle proteins as containing oxidized tryptophan residues were studied using postsource decay and collision-induced dissociation (CID) in matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF)/TOF mass spectrometry (MS) and CID in an electrospray ionization (ESI) double quadrupole TOF-MS. For each sequence, a panel of five different peptides containing Trp, 5-HTP, Kyn, NFK, or Oia residue was studied. It was always possible to identify the modified positions by the y-series and also to distinguish the different oxidation products by characteristic fragment ions in the lower mass range by tandem MS. NFK- and Kyn-containing peptides displayed an intense signal at m/z 174.1, which could be useful in identifying accordingly modified peptides by a sensitive precursor ion scan. Most importantly, it was always possible to distinguish isomeric 5-HTP and Oia residues. In ESI- and MALDI-MS/MS, this was achieved by the signal intensity ratios of two signals obtained at m/z 130.1 and 146.1. In addition, high collision energy CID in the MALDI-TOF/TOF-MS also permitted the identification of these two isomeric residues by their v- and w-ions, respectively.
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Affiliation(s)
- Toni Todorovski
- Institute of Bioanalytical Chemistry, Faculty of Chemistry and Mineralogy, Universität Leipzig, Leipzig, Germany
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Liu B, Wang DJ, Liu BM, Wang X, He LL, Wang J, Xu SK. The influence of ultrasound on the fluoroquinolones antibacterial activity. ULTRASONICS SONOCHEMISTRY 2011; 18:1052-1056. [PMID: 21353619 DOI: 10.1016/j.ultsonch.2011.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2010] [Revised: 01/28/2011] [Accepted: 02/02/2011] [Indexed: 05/30/2023]
Abstract
In this work, the antibacterial effect of fluoroquinolones (FQs) upon Escherichia coli (E.coli) was measured with and without application of 40 kHz ultrasound (US) stimulation. The research results demonstrated that simultaneous application of 40 kHz US apparently enhanced the antibacterial effectiveness of FQs. That is, the synergistic effect was observed and the bacterial viability was reduced when FQs and US were combined. In addition, various influencing factors, such as FQs drug concentration, US irradiation time and solution temperature, on the inhibition of E.coli were also investigated. The antibacterial activity was enhanced apparently with increasing of FQs drug concentration, US irradiation time and solution temperature. Furthermore, we discussed preliminarily the mechanism of US enhanced antibacterial activity. Results show that US can activate FQs to produce reactive oxygen species (ROS) indeed, which are mainly determined as superoxide radical anion (·O(2)(-)) and hydroxyl radical (·OH).
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Affiliation(s)
- Bin Liu
- Department of Pharmacy, Liaoning University, Shenyang, PR China.
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