Molecular mechanism of Mg-ATPase activity.

Mg-ATPase is very important in living organisms. To better understand the molecular mechanism of Mg-ATPase activity, we applied the method of kinetic analysis of multi-sited enzyme systems; this is a suitable approach used for kinetic investigation of multi-sited enzyme systems. The study of Mg-ATPase has demonstrated: (1) It is a multi-sited enzyme system whose functional unit is minimum a dimmer; (2) Its substrate is MgATP, while free ATP and Mg(2+) appear to be the enzyme modifiers with a dual effect; (3) The enzyme system for MgATP has at least three sites: i.e., the essential activator, full inhibitor, and partial effect modifiers sites; (4) Mg-ATPase carries out Mg(2+) transport through the 1Mg(2+):1ATP stochiometry. Based on the results of these analyses, the kinetic scheme for Mg-ATPase has been developed.