(Na+ + K+)-ATPase: function, structure, and conformations.

Abstract

Na+- and K+ -dependent adenosine triphosphatase [(Na+ + K+)-ATPase] plays a pivotal role in the homeostasis of Na+, K+, and Ca2+ in cells. Although the structural and enzymatic characteristics of this enzyme are being rapidly elucidated, the mechanisms underlying the vectorial movement of ions remain unclear. An understanding of the mechanism and localization of this enzyme is of importance in the study of epilepsy, since a possible defect leading to epilepsy may involve the inability of cellular elements to clear extracellular K+. Studies of conformational changes associated with the binding of specific ligands to the enzyme are being used to understand better the mechanism of the (Na+ + K+)-ATPase found in nervous tissue and transporting epithelia.