The hydrogen/potassium ATPase, or gastric proton pump, belongs to a family of P-type cation-transporting ATPases. This family of ATPases shares a number of functional and structural similarities including the common feature of consisting of an alpha and beta subunit. Like the ubiquitous sodium/potassium ATPase, the hydrogen/potassium ATPase consists of a large transmembrane catalytic subunit, termed the alpha-subunit which contains sites for ATP binding and phosphorylation, and an associated smaller glycoprotein, termed the beta-subunit which may play a role in maintaining the structural and functional integrity of the complex.
