GASTRIC H+ K+-ATPASE

The gastric H+/K+-ATPase is an enzyme located in the tubulovesicular s ystem and the apical membrane of the parietal cell and plays a crucial role in the process of gastric acid secretion. The enzyme catalyses a n electroneutral exchange of H+ versus K+. It consists of a catalytic a-subunit and a heavily glycosylated beta-subunit, both of which are r ather homologous to their counterparts in Na+/K+-ATPase. In this revie w, molecular and genetic aspects of this enzyme are reviewed with refe rence to similar enzymes in other tissues.