Biochemical characterization of three mutant isozymes of erythrocyte pyruvate kinase: PK-“Gainesville,” PK-“San Juan,” and PK-“Cape Canaveral”

Pyruvate kinase was partially purified from erythrocytes of three unrelated, nonconsaguineous patients with chronic hemolytic anemia of differing clinical severities. Characterization of the defective PK isozymes by internationally standardized criteria indicated that one (PK-“Gainesville”) had severely impaired substrate affinity, another (PK-“San Juan”) had markedly reduced residual activity, and the third (PK-“Cape Canaveral”) had a combination of milder defects. Each appears representative of subsets emerging from the heterogeneous molecular defects that make up pyruvate kinase deficiency.