Superoxide reacts with nitric oxide to nitrate tyrosine at physiological pH via peroxynitrite
Superoxide reacts with nitric oxide to nitrate tyrosine at physiological pH via peroxynitrite
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DOI：
10.1074/jbc.m910433199
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发表时间：
2000-10-20
影响因子：
4.8
通讯作者：
Beckman, JS
中科院分区：
文献类型：
--
作者：
Reiter, CD;Teng, RJ;Beckman, JS
酪氨酸硝化是一氧化氮与超氧化物反应产生的过氧亚硝酸根（ONOO-）的广泛使用的标记物。Pfeiffer和Mayer（Pfeiffer，S.，和Mayer，B，（1998）J. Biol; Chem，273，27280-27285）报道了由次黄嘌呤加黄嘌呤氧化酶产生的超氧化物与由精胺NONOate产生的一氧化氮组合在中性pH下不硝酸化酪氨酸。他们提出，一氧化氮和超氧化物在中性pH下形成反应性较低的中间体，其不同于不硝酸化酪氨酸的预先形成的碱性过氧亚硝酸盐，使用停流分光光度计快速混合超氧化钾与一氧化氮在pH 7.4，我们报告，一个中间体的光谱和动力学相同的预先形成的碱性顺式过氧亚硝酸盐形成100%的收率。此外，该中间体以与预形成的过氧亚硝酸盐相同的产率和相同的速率硝化酪氨酸。在有氧条件下，在没有超氧化物的情况下，等效浓度的一氧化氮没有产生可检测浓度的硝基酪氨酸。二氧化碳增加硝化效率的一氧化氮加超氧化物的过氧亚硝酸盐，在实验中使用黄嘌呤氧化酶作为超氧化物的来源，酪氨酸硝化基本上抑制尿酸形成的次黄嘌呤氧化，这是足以占缺乏酪氨酸硝化以前报道。我们的结论是过氧亚硝酸盐形成的一氧化氮与超氧化物在生理pH值的反应仍然是一个重要的物种负责酪氨酸硝化在体内。
Tyrosine nitration is a widely used marker of peroxynitrite (ONOO-) produced from the reaction of nitric oxide with superoxide. Pfeiffer and Mayer (Pfeiffer, S., and Mayer, B, (1998) J. Biol; Chem, 273, 27280-27285) reported that superoxide produced from hypoxanthine plus xanthine oxidase in combination with nitric oxide produced from spermine NONOate did not nitrate tyrosine at neutral pH, They suggested that nitric oxide and superoxide at neutral pH form a less reactive intermediate distinct from preformed alkaline peroxynitrite that does not nitrate tyrosine, Using a stopped-flow spectrophotometer to rapidly mix potassium superoxide with nitric oxide at pH 7.4, we report that an intermediate spectrally and kinetically identical to preformed alkaline cis-peroxynitrite was formed in 100% yield. Furthermore, this intermediate nitrated tyrosine in the same yield and at the same rate as preformed peroxynitrite. Equivalent concentrations of nitric oxide under aerobic conditions in the absence of superoxide did not produce detectable concentrations of nitrotyrosine. Carbon dioxide increased the efficiency of nitration by nitric oxide plus superoxide to the same extent as peroxynitrite, In experiments using xanthine oxidase as a source of superoxide, tyrosine nitration was substantially inhibited by urate formed from hypoxanthine oxidation, which was sufficient to account for the lack of tyrosine nitration previously reported. We conclude that peroxynitrite formed from the reaction of nitric oxide with superoxide at physiological pH remains an important species responsible for tyrosine nitration in vivo.