The apparent glutathione oxidase activity of gamma-glutamyl transpeptidase. Chemical mechanism.
Year: 1980
Type: article
Abstract: The apparent glutathione oxidase activity of gamma-glutamyl transpeptidase is due to nonenzymatic oxidation and transhydrogenation reactions of cysteinylglycine, an enzymatic product formed from glutathione by hydrolysis or autotranspeptidation. Since cysteinylglycine reacts with oxygen more rapidly than does glutathione, the rate of disulfide formation is increased and either cystinyl-bis-glycine or the mixed disulfide of cysteinylglycine and glutathione forms as an intermediate product. Nonenzymatic transhydrogenation reactions of these disulfides with glutathione yield glutathione disulfide and thus account for the apparent glutathione oxidase activity of gamma-glutamyl transpeptidase. A sensitive assay for glutathione oxidation is described, and it is shown that covalent inhibitors of gamma-glutamyl transpeptidase abolish the oxidase activity of the purified enzyme and of crude homogenates of mouse and rat kidney.
Source: Journal of Biological Chemistry
Authors: O.W. Griffith, S.S. Tate
Institution: Cornell University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1584613840