PEROXYNITRITE-MEDIATED TYROSINE NITRATION CATALYZED BY SUPEROXIDE-DISMUTASE
PEROXYNITRITE-MEDIATED TYROSINE NITRATION CATALYZED BY SUPEROXIDE-DISMUTASE
复制标题
DOI：
10.1016/0003-9861(92)90431-u
复制
发表时间：
1992-11-01
影响因子：
3.9
通讯作者：
BECKMAN, JS
中科院分区：
文献类型：
--
作者：
ISCHIROPOULOS, H;ZHU, L;BECKMAN, JS
过氧亚硝酸盐（ONOO−）是超氧化物（O2−）和一氧化氮（NO）的反应产物，可能是炎症、败血症和缺血/再灌注期间产生的主要细胞毒性剂。牛Cu，Zn超氧化物歧化酶与过氧亚硝基阴离子反应生成一种稳定的黄色蛋白质结合加合物，经鉴定为硝基酪氨酸。过氧亚硝酸盐修饰的超氧化物歧化酶的紫外-可见光谱是高度pH依赖性的，在碱性pH值下，在438 nm处表现出一个峰，在酸性pH值下，转移到356 nm处。通过用四硝基甲烷处理的Cu，Zn超氧化物歧化酶获得了一个等效的紫外-可见光谱。过亚硝酸根修饰的Cu，Zn超氧化物歧化酶的拉曼光谱中包含了真正的硝基酪氨酸的拉曼光谱。该反应对过氧亚硝酸盐具有特异性，因为一氧化氮（NO）、二氧化氮（NO2）、亚硝酸盐（NO2−）或硝酸盐（NO3−）不会形成大量的硝基酪氨酸。从Cu，Zn超氧化物歧化酶中去除铜防止由过氧亚硝酸根形成硝基酪氨酸。该机制似乎涉及过氧亚硝酸盐最初与活性位点铜反应，形成具有硝鎓离子（NO2+）反应性的中间体，然后在超氧化物歧化酶的第二分子上硝酸化酪氨酸。在无外源酚类物质存在下，酪氨酸的硝化速率与Cu，Zn超氧化物歧化酶浓度呈二级动力学关系，速率为1.0 ± 0.1m−1· s−1。过氧亚硝酸盐介导的酪氨酸硝化也观察到锰和铁超氧化物歧化酶以及其他含铜蛋白质。
Peroxynitrite (ONOO−), the reaction product of superoxide (O2−) and nitric oxide (NO), may be a major cytotoxic agent produced during inflammation, sepsis, and ischemia/reperfusion. Bovine Cu,Zn superoxide dismutase reacted with peroxynitrite to form a stable yellow protein-bound adduct identified as nitrotyrosine. The uv-visible spectrum of the peroxynitrite-modified superoxide dismutase was highly pH dependent, exhibiting a peak at 438 nm at alkaline pH that shifts to 356 nm at acidic pH. An equivalent uv-visible spectrum was obtained by Cu,Zn superoxide dismutase treated with tetranitromethane. The Raman spectrum of authentic nitrotyrosine was contained in the spectrum of peroxynitrite-modified Cu,Zn superoxide dismutase. The reaction was specific for peroxynitrite because no significant amounts of nitrotyrosine were formed with nitric oxide (NO), nitrogen dioxide (NO2), nitrite (NO2−), or nitrate (NO3−). Removal of the copper from the Cu,Zn superoxide dismutase prevented formation of nitrotyrosine by peroxynitrite. The mechanism appears to involve peroxynitrite initially reacting with the active site copper to form an intermediate with the reactivity of nitronium ion (NO2+), which then nitrates tyrosine on a second molecule of superoxide dismutase. In the absence of exogenous phenolics, the rate of nitration of tyrosine followed second-order kinetics with respect to Cu,Zn superoxide dismutase concentration, proceeding at a rate of 1.0 ± 0.1m−1· s−1. Peroxynitrite-mediated nitration of tyrosine was also observed with the Mn and Fe superoxide dismutases as well as other copper-containing proteins.