Pyruvate kinase deficiency hemolytic anemia: enzymatic characterization studies in twelve patients.

Erythrocyte pyruvate kinase from twelve patients with hereditary erythrocyte pyruvate kinase (PK) deficiency was investigated according to the recommended methods for the characterization of red cell pyruvate kinase variants. Family members were also studied. Abnormalities were frequently noted in the affinity for the substrate, phosphoenolpyruvate; allosteric activator, fructose-1,6-diphosphate; allosteric inhibitor, ATP; and also in heat stability and electrophoretic pattern. Several different PK variants were identified. Polyacrylamide gel electrophoresis revealed the presence of immature activity bands in the red cells of some patients. These bands presumably represent residuals of isozymes produced during the evolution of erythrocyte PK, and may occur as a compensatory mechanism for the defective isozyme.