Comparative study of human M2-type pyruvate kinases isolated from human leukocytes and erythrocytes of a patient with red cell pyruvate kinase hyperactivity.

M2-type pyruvate kinases (M2-PK) have been isolated from human leukocytes and from the erythrocytes of a patient with erythrocyte PK hyperactivity. The kinetic characteristics of the patient erythrocyte M2-PK were similar to those of leukocyte M2-PK except for the Hill coefficient of phosphoenol pyruvate kinetics that showed little difference in the values. The patient erythrocyte M2-PK displayed complete immunological identity with leukocyte M2-PK in immunodiffusion, immunoblotting and immunoneutralization. The sensitivity to proteolysis by trypsin and the electrophoretic migration in different conditions were similar for the M2-PK of both origins. These results suggest an identity between this M2-PK abnormally present in erythrocytes and the M2-PK from leukocytes.