A possible involvement of glutathione in the detoxication of sulfite.
Inorganic sulfite may be detoxified by conversion to S-sulfocysteine. We demonstrate this conversion by a series of enzyme-catalyzed steps as follows. Inorganic sulfite reacts with glutathione disulfide by a thiol transferase catalyzed reaction as previously demonstrated. The S-sulfoglutathione formed is then converted by gamma-glutamyltranspeptidase to S-sulfocysteinylglycine and the latter finally hydrolyzed to S-sulfocysteine by a renal dipeptidase. S-Sulfoglutathione is a substrate for gamma-glutamyl-transpeptidase as effective as glutathione itself. Furthermore, S-sulfocysteinylglycine is cleaved as efficiently as cysteinylglycine by a renal dipeptidase at high substrate concentrations but somewhat less efficiently at low substrate concentrations.
Kågedal
B
B
Källberg
M
M
Sörbo
B
B
D000818:Animals; D002417:Cattle; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism*; D019803:Glutathione Disulfide; D005998:Glycine / Q000378:metabolism; D008658:Inactivation, Metabolic; D007700:Kinetics; D008956:Models, Chemical; D013447:Sulfites / Q000378:metabolism*; D005723:gamma-Glutamyltransferase / Q000378:metabolism
D013447:Sulfites; C011119:S-sulphocysteine; D005723:gamma-Glutamyltransferase; D005978:Glutathione; D003545:Cysteine; D005998:Glycine; D019803:Glutathione Disulfide