Erythrocyte Hexokinase Isoenzyme Patterns in Hereditary Hemoglobinopathies

Abstract

Three forms of hexokinase activity can be demonstrated in hemolysates of normal human erythrocytes by starch-gel electrophoresis. The similarity of these isoenzymes to Types I, II and III hexokinases found in other mammalian species has been confirmed by isolation of Types I and II erythrocyte hexokinases by chromatography on DEAE-cellulose. Type II is the predominant isoenzyme in the erythrocytes of newborn infants, but it is present in low or undetectable levels in those of normal adults. The presence of significant Type II hexokinase activity does not appear to be a function of erythrocyte age; increased activity has been demonstrated in the erythrocytes of adults who are homozygous for hemoglobins S, C or F or who are heterozygous for hemoglobins S or F. These observations suggest a previously unsuspected relation between the regulation of hemoglobin synthesis and the enzymatic composition of the erythrocyte.