The Role of Nonhemoglobin Proteins and Reduced Glutathione in the Protection of Hemoglobin from Oxidation in Vitro.

A deficiency of reduced glutathione in erythrocytes of freshly shed blood (1-4) or in erythrocytes exposed to certain chemical compounds (5) has been associated with shorter red cell survival and, in most cases, with the accumulation of oxidation products of hemoglobin, including methemoglobin, sulfhemoglobin, and Heinz bodies. Studies of "primaquine-sensitive" hemolytic disease have emphasized as a characteristic feature an "unstable" reduced glutathione (GSH) in the red cells, attributed to limited availability of reduced TPN (TPNH), the result, in turn, of a deficiency of the enzyme, glucose-6-phosphate dehydrogenase (G6PD). Despite extensive studies of G6PD deficiency, it is still uncertain whether the observations on reduced glutathione are of pathogenetic significance or are incidental. There is even less information on the role of glutathione in certain cases of congenital methemoglobinemia (1) and in hemolytic disease with (3, 4, 6) or without (2) inclusion bodies, which have been associated with abnormalities of glutathione. Although these cases may suggest that reduced glutathione in the erythrocyte may be the final common pathway for various disorders affecting oxidative hemolysis, the evidence conflicts as to how, if at all, glutathione protects the healthy erythrocyte from oxidative hemolysis. Mills (7-9) and Randall (7), after studies of rat blood, concluded that GSH protects hemoglobin from deleterious oxidative agents only in the presence of an additional factor, an enzyme they termed glutathione peroxidase. Studies of