Effect of the redox state of the red blood cell components on the inactivation of glutathione peroxidase by divicine.

Abstract

The redox state of red blood cell components was found to have profound effects on the specific inactivation of erythrocyte glutathione (GSH) peroxidase by divicine, a hydroquinone imine molecule of fava beans likely to be responsible, through redox cycling, of the oxidative damage of red blood cells ultimately resulting in the hemolysis of favism. Oxidation of hemoglobin is a necessary step for the inactivation to take place, apparently as a H2O2-MetHb adduct. On the other hand, the presence of either reduced NADP or glutathione enhances the inactivating effect although NADPH inhibits the oxidation of hemoglobin, and this suggests a catalytic role for MetHb in the inactivation process.