Effect of superoxide dismutase mimics on radical adduct formation during the reaction between peroxynitrite and thiols--an ESR-spin trapping study.
Effect of superoxide dismutase mimics on radical adduct formation during the reaction between peroxynitrite and thiols--an ESR-spin trapping study.
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超氧化物歧化酶模拟物对过氧亚硝酸盐和硫醇反应过程中自由基加合物形成的影响——一项 ESR 自旋捕获研究。
DOI：
10.1006/abbi.1996.0232
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Kalyanaraman,B
中科院分区：
文献类型：
--
作者：
Karoui,H;Hogg,N;Joseph,J;Kalyanaraman,B
我们重新研究了过氧亚硝酸盐（ONOO−）介导的谷胱甘肽（GSH）、l-半胱氨酸（Cys）、N-乙酰基-d，l-青霉胺（NAP）和亚硫酸氢钠（NaHSO 3）氧化形成的自由基的形成和反应。用5，5-二甲基-1-吡咯啉-N-氧化物（DMPO）捕获硫中心自由基和超氧阴离子自由基，并通过电子自旋共振（ESR）光谱分析自由基加合物。检测到以下硫中心自由基：GSH产生的谷胱甘肽自由基（GS·）、l-半胱氨酸产生的l-半胱氨酸自由基（·Scys）、NAP产生的N-乙酰基-d，l-青霉胺硫酰基自由基（·Snap）和NaHSO 3产生的亚硫酸根阴离子自由基[式]。此外还观察到DMPO的羟基自由基加合物（DMPO/·OH）的形成。低分子量超氧化物歧化酶（SOD）模拟物完全抑制DMPO/·OH的形成。这表明DMPO/·OH是由DMPO的超氧自由基加合物衰变形成的。在SOD模拟物的存在下，DMPO-硫中心加合物更持久，表明[式]部分负责DMPO-硫基加合物的不稳定性。硫中心自由基在硫醇和亚硫酸盐被过氧亚硝酸盐氧化过程中形成，与甲酸铵反应形成二氧化碳阴离子自由基[式]我们得出结论，硫中心自由基是由硫醇和亚硫酸盐被过氧亚硝酸盐氧化产生的，其产生机制与羟基自由基无关。过氧亚硝酸盐介导的硫醇氧化的生物学意义，以及使用SOD模拟物在生物自旋捕获进行了讨论。
We have reexamined the formation and reactions of radicals formed from peroxynitrite (ONOO−)-mediated oxidation of glutathione (GSH),l-cysteine (Cys),N-acetyl-d,l-penicillamine (NAP), and sodium bisulfite (NaHSO3). Sulfur-centered and superoxide anion radicals were trapped using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and the radical adducts were analyzed by electron spin resonance (ESR) spectroscopy. The following sulfur-centered radicals were detected: glutathionyl radical (GS•) from GSH,l-cysteinyl radical (•Scys) froml-cysteine,N-acetyl-d,l-penicillamine thiyl radical (•Snap) from NAP, and sulfite anion radical[formula]from NaHSO3. Additionally the formation of the hydroxyl radical adduct of DMPO (DMPO/•OH) was observed. DMPO/•OH formation was totally inhibited by low-molecular-weight superoxide dismutase (SOD) mimics. This suggests that DMPO/•OH was formed from the decay of the superoxide radical adduct of DMPO. In the presence of SOD mimics, the DMPO-sulfur-centered adducts were more persistent, suggesting that[formula]is partially responsible for the instability of DMPO-thiyl adducts. Sulfur-centered radicals formed during oxidation of thiols and sulfite by peroxynitrite react with ammonium formate to form the carbon dioxide anion radical[formula]We conclude that sulfur-centered radicals produced from the oxidation of thiols and sulfite by peroxynitrite arise from a hydroxyl-radical-independent mechanism. Biological implications of peroxynitrite-mediated oxidation of thiols as well as the use of SOD mimics in biological spin-trapping are discussed.