Different types of glutathionylation of hemoglobin can exist in intact erythrocytes

Glutathionylation of hemoglobin (Hb) was studied by incubation of intact human erythrocytes with 1 mM tert-butylhydroperoxide (tBHP). Electrophoresis of the membranes showed a time dependent increase of membrane-bound Hb α chain until 10 min, and immunoblotting study showed that membrane-bound Hb α chain reacted with anti-glutathione antibody only after 10 min. Concomitant with the Hb α chain, membrane associated actin, spectrin, and glyceraldehyde 3-phosphate dehydrogenase reacted with the antibody. Cytosolic Hb of the control erythrocytes reacted with anti-glutathione antibody. Together with our previous paper, the present study indicates that at least three different types of glutathionylation of Hb can exist in erythrocytes. The first type is a mixed disulfide bond between reduced glutathione (GSH) and normal Hb. The second type is a disulfide bond between the cysteine 93 of metHb β chain and oxidized glutathione (GSSG), and the third type is a disulfide bond between the other cysteine residues of metHb α chain and/or metHb β chain and GSSG.