THE SYNTHESIS OF HEME AND GLOBIN IN THE MATURING HUMAN ERYTHROID CELL*

Abstract

Four healthy males received single intravenous injections of glycine-2-C14 and Fe59 as ferrous citrate. Both cummulative and incremental hemin glycine and globin glycine specific activities were determined daily for 7 days thereafter. Cummulative red cell Fe59 specific activity was also determined. The cummulative data revealed that the insertion of iron and of glycine into the heme molecule cannot be temporally separated. The incremental data was interpreted as indicating that globin is maximally synthesized at a primitive stage of red cell maturation with a linear decline of its synthetic rate as the cell matures. Hemin is maximally synthesized in mid-period of erythroid cell maturation with less synthetic activity both early and late in the maturation period.