The effect of superoxide anions (
) on red blood cells (RBC) deformability and membrane proteins was investigated using hypoxanthine-xanthine oxidase system. Exposure of RBC to
caused a marked decrease in RBC deformability with a concomitant increase in cell volume and shape changes. The RBC exposed to
also displayed pronounced degradation of membrane proteins such as band 3 protein and spectrin; new bands of low molecular weight products appeared as the original membrane proteins tended to diminish, without the appearance of high molecular weight products. Since the membrane proteins are involved in processes regulating membrane properties such as permeability and viscoelasticity, the decreased deform ability induced by
may be attributable to changes in membrane proteins. Interestingly, resealed ghosts exposed to
did not show any significant change in membrane proteins, which suggests the existence of further generation of
and subsequent production of other active oxygen species mediated by
-initiated autoxidation of hemoglobin in intact RBC. Furthermore, electrophoretic analysis suggested that active oxygens increased the endogenous proteolytic susceptibility of RBC. In conclusion, a close linkage was suggested between RBC deformability and the membrane proteins.
