RELATIONSHIP BETWEEN AGE AND PROPERTIES OF HUMAN AND RABBIT ERYTHROCYTE GLUCOSE-6-PHOSPHATE DEHYDROGENASE

The properties of human and rabbit erythrocyte glucose‐6‐phosphate dehydrogenase have been investigated during aging in vivo. The erythrocytes of different age have been prepared by 2 procedures: (a) by inducing a reticulocytosis by phenylhydrazine administration to rabbits and (b) by separating the young and old red cells of man and rabbit according to the different resistence to osmotic lysis. During aging, human and rabbit glucose‐6‐phosphate dehydrogenase shows a decrease of the catalytic activity and some marked modifications of its properties. Thermolability and NADPase‐dependent inactivation increase; the protective effect of NADP and the affinity for both glucose‐6‐phosphate and NADP substrates are decreased; no modifications have been demonstrated as regards pH optimum and electrophoretic patterns in starch gel. It is possible that these modifications begin after the expulsion of ribosome material. According to the literature concerning the behaviour of other enzymes in the physiological state and of glucose‐6‐phosphate dehydrogenase of some pathological conditions, it is possible that the modified properties of the enzyme during aging in vivo can be related to some structural modifications of the protein. Copyright © 1969, Wiley Blackwell. All rights reserved