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Alpha‐class isozymes of glutathione S‐transferase in rat liver cytosol possess glutathione peroxidase activity toward phospholipid hydroperoxide
Author(s) -
Sun Qian,
Komura Sadaaki,
Ohishi Nobuko,
Yagi Kunio
Publication year - 1996
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549600201371
Subject(s) - glutathione , biochemistry , isoelectric focusing , phospholipid hydroperoxide glutathione peroxidase , isozyme , gel electrophoresis , protein subunit , chromatofocusing , cytosol , polyacrylamide gel electrophoresis , phospholipid , gpx4 , phosphatidylcholine , affinity chromatography , microbiology and biotechnology , chemistry , gpx3 , peroxidase , biology , isoelectric point , enzyme , glutathione peroxidase , gene , membrane
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 α‐class isozymes of GST in rat liver cytosol possess glutathione peroxidase activity toward phospholipid hydroperoxide.