Acceleration of peroxynitrite oxidations by carbon dioxide.
Acceleration of peroxynitrite oxidations by carbon dioxide.
复制标题
DOI：
10.1006/abbi.1996.0131
复制
发表时间：
1996-03
影响因子：
3.9
通讯作者：
R. Uppu;G. Squadrito;W. Pryor
中科院分区：
文献类型：
--
作者：
R. Uppu;G. Squadrito;W. Pryor
停流动力学研究过氧亚硝酸盐的异构化，得到硝酸盐已进行了在富含碳酸盐的缓冲液中使用pH跳跃和碳酸酐酶作为探针。这些数据与CO2和过氧亚硝酸根阴离子迅速形成不稳定的亚硝基过氧碳酸根阴离子加合物O= N-OOCO 2-（1）的反应一致。过氧亚硝酸盐异构化的CO2催化并不伴随着亚硝酸盐、过氧化氢或其他氢过氧化物材料如过氧碳酸盐的形成。该反应经由能够促进亲电硝化反应的一种或多种氧化剂的瞬时形成而进行。O= N-OOCO_2-重排生成一个硝基碳酸根阴离子O_2N-OCO_2-（2），它在生物体系中可能作为近端氧化剂产生过氧亚硝酸根。至少有四种不同的机理类的反应，已被归因于过氧亚硝酸盐可以预见到涉及2：（a）水解为硝酸盐，（B）单电子或（c）双电子氧化，和（d）亲电硝化。考虑到过氧亚硝酸盐与二氧化碳的快速反应以及后者的普遍存在，在体外和体内复杂的过氧亚硝酸盐反应中，CO2的作用不可忽视。
Stopped-flow kinetic studies of the isomerization of peroxynitrite to give nitrate have been performed in carbonate-enriched buffers using pH jump and carbonic anhydrase as probes. The data are consistent with the reaction of CO2 and the peroxynitrite anion rapidly forming an unstable nitrosoperoxy-carbonate anion adduct, O=N-OOCO2- (1). The CO2 catalysis of the isomerization of peroxynitrite is not accompanied by the formation of nitrite, hydrogen peroxide, or other hydroperoxidic material like peroxycarbonate. The reaction proceeds via the transient formation of an oxidant or oxidants that is (are) capable of promoting electrophilic nitration reactions. We propose that O=N-OOCO2- rearranges to give a nitrocarbonate anion, O2N-OCO2- (2) which in turn, may serve as the proximal oxidant in biological systems that produce peroxynitrite. At least four different mechanistic classes of reactions that have been ascribed to peroxynitrite can be envisioned to involve 2: (a) hydrolysis to nitrate, (b) one-electron or (c) two-electron oxidations, and (d) electrophilic nitration. Given the fast reaction of peroxynitrite with carbon dioxide and the ubiquitous presence of the latter, the role of CO2 cannot be neglected in complex peroxynitrite reactions in vitro and in vivo.