Glucose-6-phosphate dehydrogenase (G6PD) deficiency is characterized by the loss of NADPH and enhanced erythrocyte oxidant sensitivity. Historically, it has been theorized that the elevated oxidant sensitivity of G6PD-deficient erythrocytes arises as the direct consequence of decreased intracellular glutathione (GSH) concentrations. To directly investigate the basis of G6PD deficiency oxidant s...