title: Activation of rat liver microsomal glutathione S-transferase by hydrogen peroxide: role for protein-dimer formation.
abstract: The mechanism of oxygen radical-dependent activation of hepatic microsomal glutathione S-transferase by hydrogen peroxide was studied. Glutathione S-transferase activity in liver microsomes was increased 1.5-fold by incubation with 0.75 mM hydrogen peroxide at 37 degrees C for 10 min, and the increase in activity was reversed by incubation with dithiothreitol. Purified glutathione S-transferase was also activated by hydrogen peroxide after incubation at room temperature, and the increase in the activity was also reversed by dithiothreitol. Immunoblotting with anti-microsomal glutathione S-transferase antibodies after sodium dodecyl sulfate-polyacrylamide gel electrophoresis of hydrogen peroxide-treated microsomes or purified glutathione S-transferase revealed the presence of a glutathione S-transferase dimer. These results indicate that the hydrogen peroxide-dependent activation of the microsomal glutathione S-transferase is associated with the formation of a protein dimer.
authors.affiliation: Laboratory of Physiology and Pharmacology, School of Health Sciences, University of the Ryukyus, Okinawa, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Aniya
authors.forename: M W
authors.initials: MW
authors.lastname: Anders
mesh_terms: D000818:Animals; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D005982:Glutathione Transferase / Q000737:chemistry / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D015151:Immunoblotting; D046911:Macromolecular Substances; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D046911:Macromolecular Substances; D006861:Hydrogen Peroxide; D005982:Glutathione Transferase; D004229:Dithiothreitol