Karoui H, Hansert B, Sand P J, Tordo P, Bohle D S, Kalyanaraman B
Biophysics Research Institute, Medical College of Wisconsin, Milwaukee 53226, USA.
Nitric Oxide. 1997 Aug;1(4):346-58. doi: 10.1006/niox.1997.0140.
Glutathionyl radical (GS.) formed during the oxidation of glutathione by tetramethylammonium peroxynitrite ([NMe4][ONOO]) was spin-trapped with 5,5'-dimethyl-1-pyrroline N-oxide (DMPO) and 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO). This radical reacted with ammonium formate to form the carbon dioxide anion radical (CO2-.). The superoxide anion formed during oxidation of GSH by peroxynitrite salt was trapped with DMPO and detected as the DMPO-hydroxyl adduct. Addition of SOD mimic completely abolished the spectrum of the hydroxyl adduct but not the spectrum of the DMPO-glutathionyl radical adduct. Addition of seleno-DL-cystine or its reduced form caused a dramatic inhibition in the formation of spin adducts, suggesting that seleno-DL-cysteine is a more effective scavenger of peroxynitrite. The oxygen uptake observed during oxidation of GSH by peroxynitrite salt was inhibited by spin traps. In the presence of catalase, approximately 50% of the oxygen consumed was restored, indicating stoichiometric conversion of O2 to H2O2 during oxidation of GSH by peroxynitrite salt. Results indicate that nitrite and glutathione disulfide are formed as the major products during oxidation of GSH by peroxynitrite.
谷胱甘肽被四甲基铵过氧亚硝酸盐（[NMe4][ONOO]）氧化过程中形成的谷胱甘肽自由基（GS.），用5,5'-二甲基-1-吡咯啉N-氧化物（DMPO）和5-二乙氧基磷酰基-5-甲基-1-吡咯啉N-氧化物（DEPMPO）进行自旋捕获。该自由基与甲酸铵反应形成二氧化碳阴离子自由基（CO2-.）。过氧亚硝酸盐氧化谷胱甘肽过程中形成的超氧阴离子用DMPO捕获，并检测为DMPO-羟基加合物。添加超氧化物歧化酶模拟物完全消除了羟基加合物的光谱，但没有消除DMPO-谷胱甘肽自由基加合物的光谱。添加硒代-DL-胱氨酸或其还原形式会显著抑制自旋加合物的形成，表明硒代-DL-半胱氨酸是过氧亚硝酸盐更有效的清除剂。过氧亚硝酸盐氧化谷胱甘肽过程中观察到的氧气吸收受到自旋捕获剂的抑制。在过氧化氢酶存在下，约50%消耗的氧气得以恢复，表明过氧亚硝酸盐氧化谷胱甘肽过程中O2化学计量转化为H2O2。结果表明，过氧亚硝酸盐氧化谷胱甘肽的主要产物是亚硝酸盐和谷胱甘肽二硫化物。
