Isozyme patterns of pyruvate kinase and differentiation of Friend leukemia cells

The isozyme patterns of glycolytic enzymes of Friend leukemia cells (FLC) were compared with those of erythrocytes and erythroblasts. Erythrocyte-specific R types of pyruvate kinase (PK) were clearly observed in phenylhydrazine-induced mouse erythroblast, and much less amount of them was also observed in Friend leukemia cells. When FLC were induced to differentiate by hexamethylene-bisacetamide (HMBA), the R types were slightly reduced. When the induction of differentiation was inhibited by 12-O-tetradecanoylphorbol 13-acetate (TPA), the R types and M2-R hybrids rather increased. These results are reverse of those obtained when hemoglobin production is used as a marker of differentiation. Isozyme patterns of lactic dehydrogenase and aldolase did not change during differentiation of FLC induced by HMBA, and were the same as those of mouse erythroblasts and erythrocytes.