OBJECTIVES: 1. More exacting tests of whether the reaction catalyzed by phosphoglycerate kinase involves a phosphoryl-enzyme. 2. Further isotopic studies on the phosphoryl transfer reaction catalyzed by phosphoglycerate mutase from wheat germ. 3. The stereochemistry of enzyme-catalyzed phosphoryl group transfer, using a phosphoryl group of known chirality. BIBLIOGRAPHIC REFERENCES: J.R. Knowles, "Whither Enzyme Mechanisms" F.E.B.S. Letters, 1976, 62 Supplement, 53. P.E. Johnson, S.G. Maister, M. Semeniva, J.M. Young and J.R. Knowles "Crystalline 3-Phospho-D-glycerate Kinase from Horse Muscle", Biochemistry 1976, 15, in press.