Peroxynitrite,a Stealthy Biological Oxidant |
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Authors: | Rafael Radi |
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Institution: | From the Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, 11800 Montevideo, Uruguay |
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Abstract: | Peroxynitrite is the product of the diffusion-controlled reaction of nitric oxide and superoxide radicals. Peroxynitrite, a reactive short-lived peroxide with a pKa of 6.8, is a good oxidant and nucleophile. It also yields secondary free radical intermediates such as nitrogen dioxide and carbonate radicals. Much of nitric oxide- and superoxide-dependent cytotoxicity resides on peroxynitrite, which affects mitochondrial function and triggers cell death via oxidation and nitration reactions. Peroxynitrite is an endogenous toxicant but is also a cytotoxic effector against invading pathogens. The biological chemistry of peroxynitrite is modulated by endogenous antioxidant mechanisms and neutralized by synthetic compounds with peroxynitrite-scavenging capacity. |
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Keywords: | Free Radicals Nitric Oxide Oxidative Stress Superoxide Dismutase (SOD) Superoxide Ion Peroxynitrite Tyrosine Nitration |
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