van der Vliet A, Hoen P A, Wong P S, Bast A, Cross C E
Center for Comparative Respiratory Biology and Medicine, Department of Internal Medicine, University of California, Davis, California 95616, USA.
J Biol Chem. 1998 Nov 13;273(46):30255-62. doi: 10.1074/jbc.273.46.30255.
Peroxynitrite (ONOO-), a potent oxidant formed by reaction of nitric oxide (NO.) with superoxide anion, can activate guanylyl cyclase and is able to induce vasodilation or inhibit platelet aggregation and leukocyte adhesion, via thiol-dependent formation of NO. Reaction of ONOO- with thiols is thought to proceed through formation of a S-nitrothiol (thionitrate; RSNO2) intermediate and yields low levels of S-nitrosothiols (thionitrites; RSNO), both of which are theoretical sources of NO. Kinetic analysis of NO. production after reaction of ONOO- with GSH established that NO. originates exclusively from the thionitrite GSNO. Further mechanistic investigations indicated that GSNO formation by ONOO- does not occur via one-electron oxidation mechanisms. Nitrosation of GSH could theoretically proceed via intermediate formation of the thionitrate GSNO2, which, after rearrangement to the corresponding sulfenyl nitrite (GSONO), can react with GSH to form GSNO and GSOH. However, no evidence for such a mechanism was found in experiments with NO2. or with the stable nitrothiol tert-butylthionitrate. Using high performance liquid chromatography with chemiluminescence detection, formation of H2O2 was observed after reaction of ONOO- with GSH under both aerobic and anaerobic conditions, at levels similar to the yield of GSNO, indicative of a direct nucleophilic nitrosation mechanism with elimination of HOO-. Our results indicate that ONOO- may contribute to S-nitrosation in vivo and that direct nitrosation of thiols or other nucleophilic substrates by ONOO- may represent an important and often overlooked component of NO. biochemistry.
过氧亚硝酸根（ONOO-）是一氧化氮（NO·）与超氧阴离子反应生成的一种强氧化剂，它可激活鸟苷酸环化酶，并能够通过硫醇依赖性生成NO来诱导血管舒张或抑制血小板聚集及白细胞黏附。ONOO-与硫醇的反应被认为是通过形成S-亚硝基硫醇（硫代硝酸盐；RSNO2）中间体进行的，并产生低水平的亚硝基硫醇（硫代亚硝酸盐；RSNO），这两者都是NO的理论来源。对ONOO-与谷胱甘肽（GSH）反应后NO生成的动力学分析表明，NO仅来源于硫代亚硝酸盐GSNO。进一步的机理研究表明，ONOO-生成GSNO并非通过单电子氧化机制。理论上，GSH的亚硝化可通过硫代硝酸盐GSNO2的中间体形成来进行，GSNO2重排为相应的亚磺酰基亚硝酸盐（GSONO）后，可与GSH反应形成GSNO和GSOH。然而，在使用NO2·或稳定的亚硝基硫醇叔丁基硫代亚硝酸盐进行的实验中未发现这种机制的证据。使用高效液相色谱-化学发光检测法，在有氧和无氧条件下ONOO-与GSH反应后均观察到了H2O2的生成，其水平与GSNO的产率相似，这表明存在一种直接亲核亚硝化机制并伴有HOO-的消除。我们的结果表明，ONOO-可能在体内促成亚硝化作用，并且ONOO-对硫醇或其他亲核底物的直接亚硝化可能是NO生物化学中一个重要且常被忽视的组成部分。
