CHARACTERISTICS OF ERYTHROCYTES OF DIFFERENT AGES. II. ENZYME ACTIVITY AND OSMOTIC FRAGILITY.

The activity of glutamic oxaloacetic transaminase, lactic acid dehydrogenase, and catalase in red cells of different ages has been studied with a serial osmotic fragility technique. Two populations of young cells, one fragile and one resistant, have been differentiated and shown to contain increased levels of glutamic oxaloacetic transaminase and average (normal) levels of catalase. Lactic acid dehydrogenase levels were shown to be increased only in the fragile population of young cells. These findings were confirmed with similar studies on abnormal red cell populations containing increased numbers of young red cells and reticulocytes. Although their identity has not been established, the results suggest that the fragile and resistant young red cell populations are composed mainly of reticulocytes and fully matured young cells, respectively.