Analysis of cyclic cascade system shows that it is a superior method for metabolic regulation of key enzymes. it provides; (a) A well regulated signal amplification which is necessary for hormonal induced responses and neurol transmission. (b) A flexible regulatory system since a large number of allosteric effectors can interact with various proteins in the cascade to vary its enzymic activity; (c) A more sensitive response with respect to the change in effector concentration by allowing a given effector to interact with more than one protein in the cascade; (d) A dynamic process for regulation instead of ON-OFF switch mechanism. All these properties have been confirmed experimentally for the monocyclic system with the adenylylation and deadenylylation of glutamine synthetase system. (2) Spatial relationship between adenylylation site and the catalytic site of glutamine synthetase was established. In addition, the existence of allosteric sites for feedback inhibitors has been reaffirmed. (3) The interrelationship between effectors and substrates in the adenylylation-deadenylylation of glutamine synthetase was established. (4) Other work includes mechanistic study of alkaline phosphatase, genetic study of UTase and UR enzymes, and the development of laser heating T-jump machine. BIBLIOGRAPHIC REFERENCES: J. R. Bale and C. Y. Huang. Mechanisms of E. coli Alkaline Phosphatase: Kinetic Evidence Contrary to the Flip-Flop Model. Fed. Proc. 36, 635, 1977. P. B. Chock, S. G. Rhee and J. J. Villafranca. Regulation of Unadenylylated GS From E. coli: Direct Evidence for Separate Binding Sites for Substrates and Feedback Inhibitors. Fed. Proc. 36, 856, 1977.