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Szabó M, Bíró V, Simon F, Fábián I. The decomposition of N-chloro amino acids of essential branched-chain amino acids: Kinetics and mechanism. JOURNAL OF HAZARDOUS MATERIALS 2020; 382:120988. [PMID: 31484104 DOI: 10.1016/j.jhazmat.2019.120988] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 07/26/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
The formation of N-chloro-amino acids is of outmost importance in water treatment technologies and also in vivo processes. These compounds are considered as secondary disinfectants and play important role in the defense mechanism against invading pathogens in biological systems. Adversary effects, such as apoptosis or necrosis are also associated with these compounds and the intermediates and final products formed during their decomposition. In the present study, the decomposition kinetics of the N-chloro derivatives of branched chain amino acids (BCAAs) - leucine, isoleucine, valine - were studied. On the basis of spectrophotometric measurements, it was confirmed that the decomposition proceeds via a spontaneous and an OH- assisted path in each case: kobs = k + kOH[OH-]. 1H, 13C NMR and MS experiments were also performed to identify the products and to monitor the progress of the reactions. It was established that the pH independent and the [OH-] dependent paths lead to the formation of the same aldehyde in each system (isovaleraldehyde, 2-methyl-butyraldehyde, and isobutyraldehyde) as a primary product. Under alkaline conditions, a portion of the aldehydes are converted into the corresponding Schiff-bases by the excess amino acid in a reversible process. A common mechanism was proposed for these reactions which postulates the formation of imines and hemiaminals as reactive intermediates.
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Affiliation(s)
- Mária Szabó
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary
| | - Vivien Bíró
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary
| | - Fruzsina Simon
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary
| | - István Fábián
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Debrecen, Hungary; MTA-DE Redox and Homogeneous Catalytic Reaction Mechanisms Research Group, University of Debrecen, Debrecen, Hungary.
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A novel chlorination-induced ribonuclease YabJ from Staphylococcus aureus. Biosci Rep 2018; 38:BSR20180768. [PMID: 30201692 PMCID: PMC6435465 DOI: 10.1042/bsr20180768] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 08/15/2018] [Accepted: 08/23/2018] [Indexed: 01/09/2023] Open
Abstract
The characteristic fold of a protein is the decisive factor for its biological function. However, small structural changes to amino acids can also affect their function, for example in the case of post-translational modification (PTM). Many different types of PTMs are known, but for some, including chlorination, studies elucidating their importance are limited. A recent study revealed that the YjgF/YER057c/UK114 family (YjgF family) member RidA from Escherichia coli shows chaperone activity after chlorination. Thus, to identify the functional and structural differences of RidA upon chlorination, we studied an RidA homolog from Staphylococcus aureus: YabJ. The overall structure of S. aureus YabJ was similar to other members of the YjgF family, showing deep pockets on its surface, and the residues composing the pockets were well conserved. S. aureus YabJ was highly stable after chlorination, and the chlorinated state is reversible by treatment with DTT. However, it shows no chaperone activity after chlorination. Instead, YabJ from S. aureus shows chlorination-induced ribonuclease activity, and the activity is diminished after subsequent reduction. Even though the yabJ genes from Staphylococcus and Bacillus are clustered with regulators that are expected to code nucleic acid-interacting proteins, the nucleic acid-related activity of bacterial RidA has not been identified before. From our study, we revealed the structure and function of S. aureus YabJ as a novel chlorination-activated ribonuclease. The present study will contribute to an in-depth understanding of chlorination as a PTM.
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Jeelani R, Maitra D, Chatzicharalampous C, Najeemuddin S, Morris RT, Abu-Soud HM. Melatonin prevents hypochlorous acid-mediated cyanocobalamin destruction and cyanogen chloride generation. J Pineal Res 2018; 64:10.1111/jpi.12463. [PMID: 29247550 PMCID: PMC5843513 DOI: 10.1111/jpi.12463] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/05/2017] [Indexed: 12/15/2022]
Abstract
Hypochlorous acid (HOCl) is a potent cytotoxic oxidant generated by the enzyme myeloperoxidase (MPO) in the presence of hydrogen peroxide (H2 O2 ) and chloride (Cl- ). Elevated levels of HOCl play an important role in various pathological conditions through oxidative modification of several biomolecules. Recently, we have highlighted the ability of HOCl to mediate the destruction of the metal-ion derivatives of tetrapyrrole macrocyclic rings such as hemoproteins and vitamin B12 (VB12 ) derivatives. Destruction of cyanocobalamin, a common pharmacological form of VB12 mediated by HOCl, results in the generation of toxic molecular products such as chlorinated derivatives, corrin ring cleavage products, the toxic blood agents cyanide (CN- ) and cyanogen chloride (CNCl), and redox-active free cobalt. Here, we show that melatonin prevents HOCl-mediated cyanocobalamin destruction, using a combination of UV-Vis spectrophotometry, high-performance liquid chromatography analysis, and colorimetric CNCl assay. Identification of several melatonin oxidation products suggests that the protective role of melatonin against HOCl-mediated cyanocobalamin destruction and subsequent CNCl generation is at the expense of melatonin oxidation. Collectively, this work highlights that, in addition to acting as an antioxidant and as a MPO inhibitor, melatonin can also prevent VB12 deficiency in inflammatory conditions such as cardiovascular and neurodegenerative diseases, among many others.
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Affiliation(s)
- Roohi Jeelani
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, C. S. Mott Center for Human Growth and Development, 275 E. Hancock, Detroit, MI, 48201 USA
| | - Dhiman Maitra
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, C. S. Mott Center for Human Growth and Development, 275 E. Hancock, Detroit, MI, 48201 USA
| | - Charalampos Chatzicharalampous
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, C. S. Mott Center for Human Growth and Development, 275 E. Hancock, Detroit, MI, 48201 USA
| | - Syed Najeemuddin
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, C. S. Mott Center for Human Growth and Development, 275 E. Hancock, Detroit, MI, 48201 USA
| | - Robert T. Morris
- Division of Gynecologic Oncology, Department of Oncology, Wayne State University and Karmanos Cancer Institute, Detroit, MI, 48201 USA
| | - Husam M. Abu-Soud
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, C. S. Mott Center for Human Growth and Development, 275 E. Hancock, Detroit, MI, 48201 USA
- Department of Microbiology, Immunology and Biochemistry, Wayne State University School of Medicine, Detroit, MI, 48201 USA
- Address correspondence to: Husam Abu-Soud, Department of Obstetrics and Gynecology, C. S. Mott Center for Growth and Development, Wayne State University, 275 E. Hancock Detroit, MI 48201. Tel: 313/577-6178; Fax: 313/577-8554;
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Kato Y. Neutrophil myeloperoxidase and its substrates: formation of specific markers and reactive compounds during inflammation. J Clin Biochem Nutr 2016; 58:99-104. [PMID: 27013775 PMCID: PMC4788398 DOI: 10.3164/jcbn.15-104] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 11/12/2015] [Indexed: 12/02/2022] Open
Abstract
Myeloperoxidase is an inflammatory enzyme that generates reactive hypochlorous acid in the presence of hydrogen peroxide and chloride ion. However, this enzyme also uses bromide ion or thiocyanate as a substrate to form hypobromous or hypothiocyanous acid, respectively. These species play important roles in host defense against the invasion of microorganisms. In contrast, these enzyme products modify biomolecules in hosts during excess inflammation, indicating that the action of myeloperoxidase is both beneficial and harmful. Myeloperoxidase uses other endogenous compounds, such as serotonin, urate, and l-tyrosine, as substrates. This broad-range specificity may have some biological implications. Target molecules of this enzyme and its products vary, including low-molecular weight thiols, proteins, nucleic acids, and lipids. The modified products represent biomarkers of myeloperoxidase action. Moderate inhibition of this enzyme might be critical for the prevention/modulation of excess, uncontrolled inflammatory events. Some phytochemicals inhibit myeloperoxidase, which might explain the reductive effect caused by the intake of vegetables and fruits on cardiovascular diseases.
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Affiliation(s)
- Yoji Kato
- School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan; Research Institute of Food and Nutritional Science, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, Japan
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Szabó M, Baranyai Z, Somsák L, Fábián I. Decomposition of N-Chloroglycine in Alkaline Aqueous Solution: Kinetics and Mechanism. Chem Res Toxicol 2015; 28:1282-91. [PMID: 25849302 DOI: 10.1021/acs.chemrestox.5b00084] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Mária Szabó
- Department of Inorganic and Analytical Chemistry, and ‡Department of Organic Chemistry, University of Debrecen, Debrecen, Hungary
| | - Zsolt Baranyai
- Department of Inorganic and Analytical Chemistry, and ‡Department of Organic Chemistry, University of Debrecen, Debrecen, Hungary
| | - László Somsák
- Department of Inorganic and Analytical Chemistry, and ‡Department of Organic Chemistry, University of Debrecen, Debrecen, Hungary
| | - István Fábián
- Department of Inorganic and Analytical Chemistry, and ‡Department of Organic Chemistry, University of Debrecen, Debrecen, Hungary
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