Effects of metal ions on Mg2+-ATPase activity in plasma membranes isolated from the rat uterus

In this study, we investigated the in vitro effects of metal ions on Mg2+-ATPase activity in isolated membranes from rat uterus. The effects of increasing concentrations of metal salts (CrCl2, CuSO4, HgCl2 and ZnSO4) show sigmoidal and almost complete inhibition relative to the control enzyme activity. According to the IC50, the ATPase possesses greater sensibility to Zn2+ > Cu2+ congruent to Cr3+ congruent to Hg2+, while other metal salts exhibit the following inhibition: CdCl2 55%, CsCl 64.5% and SrCl2 58%. Here we demonstrated that the physicochemical properties of these metals are of importance in defining possible mechanisms of binding and decrease of enzyme activity.