MECHANISM OF Na+/K+–ATPase AND Mg2+–ATPase INHIBITION BY METAL IONS AND COMPLEXES*

The aim of the study was to give an overview of the mechanism of inhibition of Na+/K+–ATPase and Mg2+–ATPase activity, the enzymes playing a key role in the active transport of monovalent cations (Na+ and K+) across the cell membrane, induced by the ions of some transition (Cu2+, Zn2+, Fe2+, Co2+) and heavy (Hg2+ i Cd2+) metals, ammonium decavanadate and noble metals complexes ([PtCl2DMSO2], [AuCl4]-, [PdCl4]2-, [PdCl(dien)]+, [PdCl(Me4dien)]+). The extensive kinetic analysis was done in order to determine kinetic parameters and the mode of interaction of Na+/K+–ATPase and Mg2+–ATPase and the investigated compounds. In addition, the ability of sulphur-donor ligands (L-cysteine and glutathione), as well as EDTA, to prevent metal ions and complexes induced inhibition of Na+/K+–ATPase activity and to recover enzymatic activity was investigated. Finally, development of highly sensitive and selective analytical tools on the basis of the immobilized enzyme is discussed in this paper. Na+/K+–ATPase and Mg2+–ATPase (ecto-ATP-ase) are membrane enzymes ubiquitous in animal cells tha