Aging of the erythrocyte. VII. On the possible causes of inactivation of red cell enzymes.

The sequence of inactivation of five bovine erythrocyte enzymes (glucose-6-phosphate dehydrogenase, pyruvate kinase, lactate dehydrogenase, aspartate aminotransferase and aldolase) was compared during in vivo aging of the red blood cell and during treatment of the cells with heat, gamma-radiation and an enzymatic source of the superoxide radical anion. Amounts of oxygen free radicals comparable to those formed physiologically in the cells were able to induce considerable inactivation of some enzymes; in no case was the physiological sequence of inactivation reproduced. These results seem to argue for a multifactorial inactivation of red cell enzymes during intravascular aging of the erythrocyte.