[Deficiency of pyruvate kinase in erythrocytes: biochemical studies. Preliminary communication].

Pyruvate kinase deficiency was found to be the causative factor in a family with nonspherocytic hemolytic anemia. Biochemical findings were the following: decrease in adenosine-5'-triphosphate (ATP) concentration (59 micromoles per 100 ml of erytrocytes; normal: 150 +/- 59), increase in 2,3-diphosphoglycerate (2,3-DPG) concentration (13611 micromoles per 100 ml of erythrocytes; normal: 480 +/- 80) and low level of pyruvate kinase activity (955 U) mmol Hb; normal 2700 +/- 498. The deficiency of enzyme activity in the hexose-monophosphate shunt was excluded on bases of normal or elevated glucose-6-phosphate and 6-phosphogluconate dehydrogenase activities, normal reduced glutathione concentration and normal glutathione stability in vitro. The Michaelis constant for phosphoenolpyruvate of the patient's pyruvate kinase was found to be normal; thus, the mutation affected only the Vmax of the enzyme.