Shi X, Rojanasakul Y, Gannett P, Liu K, Mao Y, Daniel L N, Ahmed N, Saffiotti U
Laboratory of Experimental Pathology, National Cancer Institute, Bethesda, Maryland 20892-0041.
J Inorg Biochem. 1994 Nov 1;56(2):77-86. doi: 10.1016/0162-0134(94)85039-9.
Electron spin resonance (ESR) spin trapping was utilized to investigate the reaction of peroxynitrite with thiols and ascorbate at physiological pH. The spin trap used was 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The reaction of peroxynitrite with DMPO generated 5,5-dimethylpyrrolidone-(2)-oxy-(1) (DMPOX). Formate enhanced the peroxynitrite decomposition but did not generate any detectable amount of formate-derived free radicals. Thus, the spin trapping measurements provided no evidence for hydroxyl (.OH) radical generation in peroxynitrite decomposition at physiological pH. Thiols (glutathione, cysteine, and penicillamine) and ascorbate reacted with peroxynitrite to generate the corresponding thiyl and ascorbyl radicals. The one-electron oxidation of thiols by peroxynitrite may be one of the important mechanisms for peroxynitrite-induced toxicity and ascorbate may provide a detoxification pathway.
利用电子自旋共振（ESR）自旋捕集技术研究了过氧亚硝酸盐在生理pH值下与硫醇和抗坏血酸盐的反应。所用的自旋捕集剂是5,5-二甲基-1-吡咯啉N-氧化物（DMPO）。过氧亚硝酸盐与DMPO反应生成5,5-二甲基吡咯烷酮-(2)-氧基-(1)（DMPOX）。甲酸盐促进了过氧亚硝酸盐的分解，但未产生任何可检测量的源自甲酸盐的自由基。因此，自旋捕集测量未提供在生理pH值下过氧亚硝酸盐分解过程中产生羟基（·OH）自由基的证据。硫醇（谷胱甘肽、半胱氨酸和青霉胺）和抗坏血酸盐与过氧亚硝酸盐反应生成相应的硫自由基和抗坏血酸自由基。过氧亚硝酸盐对硫醇的单电子氧化可能是过氧亚硝酸盐诱导毒性的重要机制之一，而抗坏血酸盐可能提供一条解毒途径。
