Activation and Inhibition of the Mg-Ca-ATPase from E. coli by Mg2+ and Ca2+

Abstract

Abstract Mg-Ca-ATPase, E. coli, Activation, Inhibition MgATP or CaATP is the substrate of the Mg-Ca-ATPase. At low Mg2+-or Ca2+-concentrations the ATPase is activated by Mg2+ or Ca2+, the activator being essential for activity. At higher Mg2+-or Ca2+-concentrations the Mg-Ca-ATPase is inhibited competitively. Thus the real Km is smaller than reported in the literature. H+ competes with Mg2+ or Ca2+ for the metal binding sites.