Kinetics and mechanism of the hydrolysis of the phosphoryl bond in the active site of alkaline phosphatase

An acid-base mechanism of the hydrolysis of the phosphoryl bond by alkaline phosphatase via the formation of two intermediate enzyme-substrate complexes, ES1 and ES2, with two corresponding chains of redistribution of bonds. A kinetic analysis within the framework of a three-step with consideration given to the formation of the phosphorylated enzyme (E-P) was performed. Based on this analysis, the rate constants, k(2), k(3), and K-S, for the reaction with n-nitrophenylphosphate, a model substrate, were determined. The structure of the conformational lock in various phosphatases and its role in the stabilization of the enzyme were considered.