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Ramos LD, Gomes TMV, Quintiliano SAP, Premi S, Stevani CV, Bechara EJH. Biological Schiff bases may generate reactive triplet carbonyls and singlet oxygen: A model study. Free Radic Biol Med 2022; 191:97-104. [PMID: 36049617 DOI: 10.1016/j.freeradbiomed.2022.08.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/24/2022]
Affiliation(s)
- Luiz D Ramos
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Brazil; Centro Universitário Anhanguera - UniA, Brazil
| | - Thiago M V Gomes
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Brazil; Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Brazil
| | - Samir A P Quintiliano
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Brazil
| | - Sanjay Premi
- Moffitt Cancer Center, Department of Tumor Biology, Tampa, FL, USA
| | - Cassius V Stevani
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Brazil; Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Brazil
| | - Etelvino J H Bechara
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, Brazil; Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Brazil.
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2
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Gonçalves LCP, Massari J, Licciardi S, Prado FM, Linares E, Klassen A, Tavares MFM, Augusto O, Di Mascio P, Bechara EJH. Singlet oxygen generation by the reaction of acrolein with peroxynitrite via a 2-hydroxyvinyl radical intermediate. Free Radic Biol Med 2020; 152:83-90. [PMID: 32145303 DOI: 10.1016/j.freeradbiomed.2020.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 02/26/2020] [Accepted: 03/02/2020] [Indexed: 01/10/2023]
Abstract
Acrolein (2-propenal) is an environmental pollutant, food contaminant, and endogenous toxic by-product formed in the thermal decomposition and peroxidation of lipids, proteins, and carbohydrates. Like other α,β-unsaturated aldehydes, acrolein undergoes Michael addition of nucleophiles such as basic amino acids residues of proteins and nucleobases, triggering aging associated disorders. Here, we show that acrolein is also a potential target of the potent biological oxidant, nitrosating and nitrating agent peroxynitrite. In vitro studies revealed the occurrence of 1,4-addition of peroxynitrite (k2 = 6 × 103 M-1 s-1, pH 7.2, 25 °C) to acrolein in air-equilibrated phosphate buffer. This is attested by acrolein concentration-dependent oxygen uptake, peroxynitrite consumption, and generation of formaldehyde and glyoxal as final products. These products are predicted to be originated from the Russell termination of •OOCH=CH(OH) radical which also includes molecular oxygen at the singlet delta state (O21Δg). Accordingly, EPR spin trapping studies with the 2,6-nitrosobenzene-4-sulfonate ion (DBNBS) revealed a 6-line spectrum attributable to the 2-hydroxyvinyl radical adduct. Singlet oxygen was identified by its characteristic monomolecular IR emission at 1,270 nm in deuterated buffer, which was expectedly quenched upon addition of water and sodium azide. These data represent the first report on singlet oxygen creation from a vinylperoxyl radical, previously reported for alkyl- and formylperoxyl radicals, and may contribute to better understand the adverse acrolein behavior in vivo.
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Affiliation(s)
- Leticia C P Gonçalves
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Júlio Massari
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Saymon Licciardi
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil; Departamento Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil
| | - Fernanda M Prado
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Edlaine Linares
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Aline Klassen
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Marina F M Tavares
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Ohara Augusto
- Departamento de Bioquímica, 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; Departamento Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema, SP, Brazil.
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3
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Matsukawa Y, Hirashita T, Araki S. Reactions between 5-Nitroso-1,3-diphenyltetrazolium Salts and Electron-Rich Arenes, Amines, Thiophenol, Sulfoxides, and Thioanisole. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2019. [DOI: 10.1246/bcsj.20180315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Yuta Matsukawa
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Tsunehisa Hirashita
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
| | - Shuki Araki
- Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, Aichi 466-8555, Japan
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4
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Timmins GS, Wei X, Hawkins CL, Taylor RJK, Davies MJ. The synthesis and use of a15N and2H isotopically-labelled derivative of the spin-trap 3, 5-dibromo-4-nitrosobenzenesulphonic acid. Redox Rep 2016; 2:407-10. [DOI: 10.1080/13510002.1996.11747082] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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5
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Genaro-Mattos TC, Queiroz RF, Cunha D, Appolinario PP, Di Mascio P, Nantes IL, Augusto O, Miyamoto S. Cytochrome c Reacts with Cholesterol Hydroperoxides To Produce Lipid- and Protein-Derived Radicals. Biochemistry 2015; 54:2841-50. [DOI: 10.1021/bi501409d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Thiago C. Genaro-Mattos
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Raphael F. Queiroz
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
- Departamento
de Química e Exatas, Universidade Estadual do Sudoeste da Bahia, Jequié, BA 45200-000, Brazil
| | - Daniela Cunha
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Patricia P. Appolinario
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Paolo Di Mascio
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Iseli L. Nantes
- Centro
de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP 09210-580, Brazil
| | - Ohara Augusto
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
| | - Sayuri Miyamoto
- Departamento
de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP 05508-000, Brazil
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6
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Prakash GS, Gurung L, Schmid PC, Wang F, Thomas TE, Panja C, Mathew T, Olah GA. ipso-Nitrosation of arylboronic acids with chlorotrimethylsilane and sodium nitrite. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.01.138] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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Venpin WKPF, Kennedy EM, Mackie JC, Dlugogorski BZ. Mechanistic Study of Trapping of NO by 3,5-Dibromo-4-Nitrosobenzene Sulfonate. Ind Eng Chem Res 2012. [DOI: 10.1021/ie302125x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Wendy K. P. F. Venpin
- Process Safety and Environment Protection Research Group, School
of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Eric M. Kennedy
- Process Safety and Environment Protection Research Group, School
of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - John C. Mackie
- Process Safety and Environment Protection Research Group, School
of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Bogdan Z. Dlugogorski
- Process Safety and Environment Protection Research Group, School
of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
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8
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Song N, Stanbury DM. Proton-coupled electron-transfer oxidation of phenols by hexachloroiridate(IV). Inorg Chem 2009; 47:11458-60. [PMID: 19006385 DOI: 10.1021/ic8015595] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
One-electron oxidation of phenol, 2,4,6-trimethylphenol, and 2,6-dimethylphenol by [IrCl(6)](2-) in aqueous solution has a simple pH dependence, indicating slow bimolecular oxidation of ArOH and faster oxidation of ArO(-). H/D kinetic isotope effects as large as 3.5 for oxidation of ArOH support concerted proton-coupled electron transfer with water as the proton acceptor.
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Affiliation(s)
- Na Song
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849, USA
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9
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Ranguelova K, Suarez J, Magliozzo RS, Mason RP. Spin trapping investigation of peroxide- and isoniazid-induced radicals in Mycobacterium tuberculosis catalase-peroxidase. Biochemistry 2008; 47:11377-85. [PMID: 18831539 DOI: 10.1021/bi800952b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new approach, the immuno-spin trapping assay, used a novel rabbit polyclonal anti-DMPO (5,5-dimethyl-1-pyrroline N-oxide) antiserum to detect protein radical-derived DMPO nitrone adducts in the hemoprotein Mycobacterium tuberculosis catalase-peroxidase (KatG). This work demonstrates that the formation of protein nitrone adducts is dependent on the concentrations of tert-BuOOH and DMPO as shown by Western blotting and an enzyme-linked immunosorbent assay (ELISA). We have also detected protein-protein cross-links formed during turnover of Mtb KatG driven by tert-butyl peroxide ( tert-BuOOH) or enzymatic generation of hydrogen peroxide. DMPO inhibits this dimerization due to its ability to trap the amino acid radicals responsible for the cross-linkage. Chemical modifications by tyrosine and tryptophan blockage suggest that tyrosine residues are one site of formation of the dimers. The presence of the tuberculosis drug isoniazid (INH) also prevented cross-linking as a result of its competition for the protein radical. Protein-DMPO nitrone adducts were also generated by a continuous flux of hydrogen peroxide. These findings demonstrated that the protein-based radicals were formed not only during Mtb KatG turnover with alkyl peroxides but also in the presence of hydrogen peroxide. Furthermore, the formation of protein-DMPO nitrone adducts was accelerated in the presence of isoniazid.
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Affiliation(s)
- Kalina Ranguelova
- Laboratory of Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, P.O. Box 12233, MD F0-01, 111 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, USA.
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10
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Bonini MG, Siraki AG, Atanassov BS, Mason RP. Immunolocalization of hypochlorite-induced, catalase-bound free radical formation in mouse hepatocytes. Free Radic Biol Med 2007; 42:530-40. [PMID: 17275685 PMCID: PMC1952183 DOI: 10.1016/j.freeradbiomed.2006.11.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Revised: 10/09/2006] [Accepted: 11/17/2006] [Indexed: 12/13/2022]
Abstract
The establishment of oxidants as mediators of signal transduction has renewed the interest of investigators in oxidant production and metabolism. In particular, H(2)O(2) has been demonstrated to play pivotal roles in mediating cell differentiation, proliferation, and death. Intracellular concentrations of H(2)O(2) are modulated by its rate of production and its rate of decomposition by catalase and peroxidases. In inflammation and infection, some of the H(2)O(2) is converted to hypochlorous acid, a key mediator of the host immune response against pathogens. In vivo HOCl production is mediated by myeloperoxidase, which uses excess H(2)O(2) to oxidize Cl(-). Mashino and Fridovich (Biochim. Biophys. Acta 956:63-69; 1988) observed that a high excess of HOCl over catalase inactivated the enzyme by mechanisms that remain unclear. The potential relevance of this as an alternative mechanism for catalase activity control and its potential impact on H(2)O(2)-mediated signaling and HOCl production compelled us to explore in depth the HOCl-mediated catalase inactivation pathways. Here, we demonstrate that HOCl induces formation of catalase protein radicals and carbonyls, which are temporally correlated with catalase aggregation. Hypochlorite-induced catalase aggregation and free radical formation that paralleled the enzyme loss of function in vitro were also detected in mouse hepatocytes treated with the oxidant. Interestingly, the novel immuno-spin-trapping technique was applied to image radical production in the cells. Indeed, in HOCl-treated hepatocytes, catalase and protein-DMPO nitrone adducts were colocalized in the cells' peroxisomes. In contrast, when hepatocytes from catalase-knockout mice were treated with hypochlorous acid, there was extensive production of free radicals in the plasma membrane. Because free radicals are short-lived species with fundamental roles in biology, the possibility of their detection and localization to cell compartments is expected to open new and stimulating research venues in the interface of chemistry, biology, and medicine.
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Affiliation(s)
- Marcelo G Bonini
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, MD F0-02, Research Triangle Park, NC 27709, USA.
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11
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Keppler AF, Cerchiaro G, Augusto O, Miyamoto S, Prado F, Di Mascio P, Comasseto JV. Organic Tellurium-Centered Radicals Evidenced by EPR Spin Trapping and Mass Spectrometry Experiments: Insights into the Mechanism of the Hydrotelluration Reaction. Organometallics 2006. [DOI: 10.1021/om060560s] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Artur F. Keppler
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
| | - Giselle Cerchiaro
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
| | - Ohara Augusto
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
| | - Sayuri Miyamoto
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
| | - Fernanda Prado
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
| | - Paolo Di Mascio
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
| | - João V. Comasseto
- Departamento de Química Fundamental and Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05508-970, São Paulo, Brazil
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12
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Lima ES, Bonini MG, Augusto O, Barbeiro HV, Souza HP, Abdalla DSP. Nitrated lipids decompose to nitric oxide and lipid radicals and cause vasorelaxation. Free Radic Biol Med 2005; 39:532-9. [PMID: 16043024 DOI: 10.1016/j.freeradbiomed.2005.04.005] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Revised: 03/03/2005] [Accepted: 04/05/2005] [Indexed: 11/19/2022]
Abstract
Nitric oxide-derived oxidants such as nitrogen dioxide and peroxynitrite have been receiving increasing attention as mediators of nitric oxide toxicity. Indeed, nitrated and nitrosated compounds have been detected in biological fluids and tissues of healthy subjects and in higher yields in patients under inflammatory or infectious conditions as a consequence of nitric oxide overproduction. Among them, nitrated lipids have been detected in vivo. Here, we confirmed and extended previous studies by demonstrating that nitrolinoleate, chlolesteryl nitrolinoleate, and nitrohydroxylinoleate induce vasorelaxation in a concentration-dependent manner while releasing nitric oxide that was characterized by chemiluminescence-and EPR-based methodologies. As we first show here, diffusible nitric oxide production is likely to occur by isomerization of the nitrated lipids to the corresponding nitrite derivatives that decay through homolysis and/or metal ion/ascorbate-assisted reduction. The homolytic mechanism was supported by EPR spin-trapping studies with 3,5-dibromo-4-nitrosobenzenesulfonic acid that trapped a lipid-derived radical during nitrolinoleate decomposition. In addition to provide a mechanism to explain nitric oxide production from nitrated lipids, the results support their role as endogenous sources of nitric oxide that may play a role in endothelium-independent vasorelaxation.
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Affiliation(s)
- Emersom S Lima
- Clinical and Toxicological Analysis Department, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, Brazil
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13
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In situ FT-IR and ex situ EPR analysis for the study of the electroreduction of carbon dioxide in N,N-dimethylformamide on a gold interface. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2004.11.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Priewisch B, Rück-Braun K. Efficient Preparation of Nitrosoarenes for the Synthesis of Azobenzenes. J Org Chem 2005; 70:2350-2. [PMID: 15760229 DOI: 10.1021/jo048544x] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] Reaction conditions are described for the oxidation of anilines furnishing nitrosoarenes and the synthesis of unsymmetrically substituted azobenzenes. In a comparative study, the catalytic oxidation of methyl 4-aminobenzoate by hydrogen peroxide was investigated, and SeO(2) proved to be superior or equal to methyl trioxorhenium (MTO) and Na(2)WO(4), respectively. Nevertheless, the application of the inexpensive, environmentally friendly, Oxone in a biphasic system proved to be more efficient, and a variety of useful nitrosoarenes for the synthesis of azo compounds were prepared in high yield and purity on a large scale.
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Affiliation(s)
- Beate Priewisch
- Technische Universität Berlin, Institut für Chemie, Strasse des 17. Juni 135, D-10623 Berlin, Germany
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15
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Cerchiaro G, Micke GA, Tavares MFM, da Costa Ferreira AM. Kinetic studies of carbohydrate oxidation catalyzed by novel isatin–Schiff base copper(II) complexes. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.06.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cash CD. Why tryptophan hydroxylase is difficult to purify: a reactive oxygen-derived species-mediated phenomenon that may be implicated in human pathology. GENERAL PHARMACOLOGY 1998; 30:569-74. [PMID: 9522177 DOI: 10.1016/s0306-3623(97)00308-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
1. Attempts and apparently successful procedures to obtain reasonable quantities of electrophoretically homogenous mammalian brain-derived tryptophan hydroxylase, (TPH), have been described, starting in the early 1970s. This work has been carried out with the primary objective to obtain specific antisera to this enzyme to map out serotonergic pathways in the nervous system. 2. By using a multitude of techniques, antisera have indeed been fabricated and employed. However, it is doubtful if pure, native TPH has ever been produced. Indeed, there is strong evidence that more than one isoform of TPH exists in the rat brain. Thus, these antisera are probably directed against TPH-derived polypeptides and not the holoenzyme(s). 3. The difficulty in the purification of TPH lies not only in its subjectivity to proteolysis, but more importantly in its probable capacity to produce superoxide leading to hydrogen perioxide formation. This, in turn, may undergo Fenton chemistry with iron at the active site of the protein to produce hydroxyl radicals that directly attack and destroy the enzyme molecule. Evidence for such a mechanism is presented together with possible protocols that might be used to produce pure stable holo TPH(s). 4. It is hypothesized that similar oxidative events may take place in vivo under certain conditions leading to pathological results. Strategies to block these events are suggested.
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Affiliation(s)
- C D Cash
- Centre de Neurochimie, Strasbourg, France
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17
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Silvester JA, Timmins GS, Davies MJ. Protein hydroperoxides and carbonyl groups generated by porphyrin-induced photo-oxidation of bovine serum albumin. Arch Biochem Biophys 1998; 350:249-58. [PMID: 9473299 DOI: 10.1006/abbi.1997.0495] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Porphyrin-sensitized photo-oxidation of bovine serum albumin results in oxidation at specific sites to produce protein radical species: at the Cys-34 residue (to give a thiyl radical) and at one or both tryptophan residues (Trp-134 and Trp-214) to give tertiary carbon-centered radicals and cause disruption of the indole ring system. This study shows that these photo-oxidation processes also consume oxygen and give rise to hydrogen peroxide, protein hydroperoxides, and carbonyl functions. The yield of hydrogen peroxide, protein hydroperoxides, and carbonyl functions is shown to be dependent on illumination time, the nature of the sensitizer, and the concentration of oxygen; the yield of hydroperoxides can also be markedly diminished by the presence of a spin trap which reacts with the initial protein radicals. The mechanism of formation of the protein hydroperoxides is suggested to be primarily through type I processes (i.e., independent of singlet oxygen), while type II (singlet oxygen) mechanisms may play a significant role in protein carbonyl formation. Reaction of the protein hydroperoxide species with metal ion complexes is shown to produce further protein-derived radicals which are predominantly present on amino acid side chains.
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Affiliation(s)
- J A Silvester
- Department of Chemistry, University of York, York, United Kingdom
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18
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Nepveu F, Souchard JP, Rolland Y, Dorey G, Spedding M. 2-2'-Pyridylisatogen, a selective allosteric modulator of P2 receptors, is a spin trapping agent. Biochem Biophys Res Commun 1998; 242:272-6. [PMID: 9446783 DOI: 10.1006/bbrc.1997.7949] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
2-2'-Pyridylisatogen (PIT) has been reported to be a relatively selective irreversible antagonist of responses to adenosine 5'-triphosphate (ATP) in some smooth muscle preparations and to be an allosteric modulator of responses to ATP at recombinant P2Y receptors from chick brain. PIT is also a potent inhibitor of mitochondrial oxidative phosphorylation. However, the compound has a unique nitrone structure, so PIT was compared with dimethyl-pyrroline-N-oxide (DMPO) as a spin trapping agent for superoxide and hydroxyl radicals using electron spin resonance (ESR). PIT was found to be a potent spin trapper of both hydroxyl and superoxide radicals. PIT was more potent than DMPO to trap the hydroxyl radical forming an adduct which was more stable than the DMPO adduct in aqueous media. PIT was an effective spin trap of hydroxyl radical in aqueous buffer at pH 7.4. PIT more slowly trapped the superoxide anion but at concentrations where DMPO trapped none.
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Affiliation(s)
- F Nepveu
- Université Paul Sabatier, Faculté des Science Pharmaceutiques, Toulouse, France
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