Abstract
Human platelets and bovine lens fibers contain lactate dehydrogenase-3 (LDH-3) as the predominant isozyme but only very faint traces of LDH-5. Since the platelets and lens fibers, like mature human erythrocytes, lack a nucleus, the results strengthen the case for a previously developed association between LDH-5 and the cell nucleus. These three cell types are mainly anaerobic, and therefore their isozyme patterns are incompatible with the theory that anaerobic tissues exhibit predominantly LDH-5 and aerobic tissues mainly LDH-1.