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Nitrosonium-catalyzed decomposition of s-nitrosothiols in solution: a theoretical and experimental study.

ABSTRACT: The decomposition of S-nitrosothiols (RSNO) in solution under oxidative conditions is significantly faster than can be accounted for by homolysis of the S-N bond. Here we propose a cationic chain mechanism in which nitrosation of nitrosothiol produces a nitrosated cation that, in turn, reacts with a second nitrosothiol to produce nitrosated disulfide and the NO dimer. The nitrosated disulfide acts as a source of nitrosonium for nitrosothiol nitrosation, completing the catalytic cycle. The mechanism accounts for several unexplained facets of nitrosothiol chemistry in solution, including the observation that the decomposition of an RSNO is accelerated by O(2), mixtures of O(2) and NO, and other oxidants, that decomposition is inhibited by thiols and other antioxidants, that decomposition is dependent on sulfur substitution, and that decomposition often shows nonintegral kinetic orders.

SUBMITTER: Zhao YL

PROVIDER: S-EPMC2519156 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature

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Nitrosonium-catalyzed decomposition of s-nitrosothiols in solution: a theoretical and experimental study.

Zhao Yi-Lei YL McCarren Patrick R PR Houk K N KN Choi Bo Yoon BY Toone Eric J EJ

Journal of the American Chemical Society 20050801 31

The decomposition of S-nitrosothiols (RSNO) in solution under oxidative conditions is significantly faster than can be accounted for by homolysis of the S-N bond. Here we propose a cationic chain mechanism in which nitrosation of nitrosothiol produces a nitrosated cation that, in turn, reacts with a second nitrosothiol to produce nitrosated disulfide and the NO dimer. The nitrosated disulfide acts as a source of nitrosonium for nitrosothiol nitrosation, completing the catalytic cycle. The mechan ...[more]

PMID: 16076198

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