Post-translational modification of human erythrocyte pyruvate kinase

Upon storage, partially purified human erythrocyte pyruvate kinase (ATP: pyruvate-phosphotransferase, E.C. 2.7.1.40) from normal individuals was found to undergo a spontaneous oxidation to a form which displayed markedly reduced activity. This modified form of the enzyme exhibited kinetic patterns similar to those frequently reported for the enzyme in cases of nonspherocytic hemolytic anemia. The data are discussed in relation to the recently proposed theory that post-translational modification of pyruvate kinase is responsible for the abnormal kinetic patterns frequently encountered for this enzyme in the disease state. Van Berkel, T. J. C., Koster, J. F., Kruyt, J. K. and Staal, G. E. J. 1973 $\text{Biochim. Biophys. Acta 321}$, 496–502].