The nonenzymatic oxidation of glutathione in the presence of plasmalike concentrations of disulfides and copper ions.
The oxidation of glutathione catalyzed by a combination of low concentrations of disulfides and copper and iron ions (as they occur in the blood plasma) was investigated and compared with data obtained in vivo studies. At pH 7.4 and 37 degrees C oxidation of glutathione (3 mmol/L) in a solution saturated with oxygen could be induced from 0 to 3, 5, 10, and 21 nmol/min and mL by the addition of 0.1, 1.0, 10, and 100 mumol/L CuCl2, respectively. The presence of 50 mumol/L cystinylbisglycine as an additional component increased the rate of oxidation by a factor between two and three. Cystine was only about one third as active as cystinylbisglycine, and trans-4,5-dihydroxy-1,2-dithiane, the disulfide derivative of dithiothreitol, was even less effective in propagating glutathione oxidation. FeCl2 in combination with the disulfides was 30 times less active than copper as a catalyst. With plasmalike concentrations of the reactants, a rate of glutathione oxidation of 0.2 to 0.8 nmol/min and mL, depending on the availability of free plasma copper, could be approximated. This rate corresponds to 8% to 30% of total plasma glutathione oxidation.
D003300:Copper / Q000097:blood / Q000494:pharmacology*; D003545:Cysteine / Q000378:metabolism; D004151:Dipeptides / Q000378:metabolism; D004220:Disulfides / Q000097:blood / Q000494:pharmacology*; D004229:Dithiothreitol / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism*; D019803:Glutathione Disulfide; D006801:Humans; D010084:Oxidation-Reduction
D004151:Dipeptides; D004220:Disulfides; C028505:cysteinylglycine; D003300:Copper; D005978:Glutathione; D003545:Cysteine; D004229:Dithiothreitol; D019803:Glutathione Disulfide