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Doctoral Thesis
DOI
10.11606/T.46.2016.tde-19082016-151826
Document
Author
Full name
Marcelo Gialluisi Bonini
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2004
Supervisor
Committee
Augusto, Ohara (President)
Campa, Ana
Isola, Rafael Radi
Kowaltowski, Alicia Juliana
Meneghini, Rogerio
Title in Portuguese
Produção e alvos biológicos de dióxido de nitrogênio e anion radical carbonato. Produção a partir de peroxinitrito-dióxido de carbono, superóxido dismutase e xantina oxidase
Keywords in Portuguese
Óxido nítrico (Estudo)
Peroxidase (Estudo)
Radicais livres (Estudo)
Superóxido dismutase (Estudo)
Abstract in Portuguese
Peroxinitrito (ONOO- + ONOOR), o produto da reação controlada por difusão do óxido nítrico com o ânion radical superóxido, tem recebido muita atenção como possível mediador dos efeitos deletérios associados a uma superprodução de óxido nítrico. O peroxinitrito é um potente oxidante que é capaz de oxidar e nitrar várias biomoléculas cujos mecanismos contribuímos para esclarecer. Particularmente relevante foi demonstrar inequívocamente, por EPR de fluxo, que a rápida reação entre peroxinitrito e o biologicamente abundante dióxido de carbono, produz dióxido de nitrogênio e ânion radical carbonato em rendimentos de aproximadamente 35%. Sugerimos então, que o peroxinitrito deveria atuar na maioria dos ambientes biológicos através de seus radicais derivados que produziriam radicais de biomoléculas. Consubstanciamos essa sugestão pelo estudo da oxidação dos biotióis cisteína, glutationa e BSA-cys34 por peroxinitrito e peroxinitrito/dióxido de carbono. Também, demonstramos que a reação entre o nitróxido tempol e os radicais derivados do peroxinitrito é uma etapa relevante para que o tempol redirecione a reatividade do peroxinitrito de nitração para nitrosação de biomoléculas. Finalmente, demonstramos que existem outras potenciais fontes biológicas de dióxido de nitrogênio e anion radical carbonato como a atividade peroxidásica da enzima superóxido dismutase e a enzima xantina oxidase.
Title in English
Biological production and targets for nitrogen dioxide and carbonate radical anion. Production by peroxynitrite-carbon dioxide, superoxide dismutase and xanthine oxidase
Keywords in English
Free radicals (Study)
Nitric oxide (Study)
Peroxidase (Study)
Superoxide dismutase (Study)
Abstract in English
Peroxynitrite (ONOO- + ONOOR), which is formed by the diffusion-controlled reaction between nitric oxide and superoxide anion, has been receiving increasing attention as a mediator of the deleterious effects associated with an overproduction of nitric oxide. Peroxynitrite is a strong oxidant that is able to oxidize and nitrate a variety of biotargets by mechanisms that this work has contributed to establish. Particularly relevant, was the unequivocal demonstration by rapid flow EPR that the rapid reaction between peroxynitrite and the biologically ubiquitous carbon dioxide produces nitrogen dioxide and carbonate radical anion in yields of around 35%. This led us to suggest that in most biological environments peroxynitrite would act through its derived radicals that would oxidize biomolecules to radicals. This hypothesis was clearly supported by our studies of biothioI (cysteine, glutathioneand BSA-cys34) oxidation by peroxynitrite and peroxynitrite/carbon dioxide. In addition, we demonstrated that the reaction between the nitroxide tempol and peroxynitrite-derived radicals is an important step of the mechanism by which tempol diverts peroxynitrite reactivity from nitration to nitrosation of biomolecules. Finally, we demonstrated that there are other potential sources of nitrogen dioxide and carbonate radical anion such as the peroxidase activity of the enzyme Cu,Zn-superoxide dismutase and the enzyme xanthine oxidase turnover.
 
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Publishing Date
2016-08-19
 
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