Sun Q, Komura S, Ohishi N, Yagi K
Institute of Applied Biochemistry, Gifu, Japan.
Biochem Mol Biol Int. 1996 May;39(2):343-52. doi: 10.1080/15216549600201371.
Selenium-independent enzymes, found in the liver cytosol of selenium deficient rats, that are capable of reducing dilinoleoyl phosphatidylcholine hydroperoxide in the presence of reduced glutathione [Guan et al., (1995) Biochem. Mol. Biol. Int., 37, 1103-1110] were purified to homogeneity by use of successive chromatography on glutathione affinity and Mono P columns. The molecular weight of the purified protein was estimated by gel filtration to be approximately 50 kDa. Upon isoelectric focusing, the purified preparation showed two protein bands having pI values of 8.6 and 8.8. Both proteins had reactivity against both 1-chloro-2,4-dinitrobenzene and dilinoleoyl phosphatidylcholine hydroperoxide in the presence of reduced glutathione. Each of them consisted of two subunits having molecular weights of 24.3 kDa and 26 kDa, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The large subunit was identified as rat glutathione S-transferase (GST) 2 (Yc subunit) based on the amino-terminal amino acid sequence analysis. The small subunit was considered to be most probably rat GST 1 (Ya subunit). From these results, we conclude that the basic alpha-class isozymes of GST in rat liver cytosol possess glutathione peroxidase activity toward phospholipid hydroperoxide.
在缺硒大鼠肝脏胞质溶胶中发现的一种不依赖硒的酶，它在还原型谷胱甘肽存在的情况下能够还原二亚油酰磷脂酰胆碱氢过氧化物[关等人，(1995)《生物化学与分子生物学国际杂志》，37，1103 - 1110]，通过在谷胱甘肽亲和柱和Mono P柱上连续层析被纯化至同质。通过凝胶过滤估计纯化蛋白的分子量约为50 kDa。经等电聚焦后，纯化制剂显示出两条蛋白带，其pI值分别为8.6和8.8。在还原型谷胱甘肽存在的情况下，这两种蛋白对1 - 氯 - 2,4 - 二硝基苯和二亚油酰磷脂酰胆碱氢过氧化物都有反应活性。通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳估计，它们各自由分子量分别为24.3 kDa和26 kDa的两个亚基组成。基于氨基末端氨基酸序列分析，大亚基被鉴定为大鼠谷胱甘肽S - 转移酶(GST)2(Yc亚基)。小亚基很可能被认为是大鼠GST 1(Ya亚基)。从这些结果我们得出结论，大鼠肝脏胞质溶胶中GST的碱性α - 类同工酶对磷脂氢过氧化物具有谷胱甘肽过氧化物酶活性。
