The H⁺/K⁺ ATPase is a heterodimeric protein, made up of α and β subunits. The α subunit has 10 TM domains and exhibits catalytic and pore functions, while the β subunit has a single TM domain, which appears to be required for intracellular trafficking and stabilising the α subunit. The ATP4A and ATP4B subunits are expressed together, while the ATP12A subunit is suggested to be expressed with the β1 (ATP1B1) subunit of the Na⁺/K⁺-ATPase [1].

The gastric H⁺/K⁺-ATPase is inhibited by proton pump inhibitors used for treating excessive gastric acid secretion, including dexlansoprazole and a metabolite of esomeprazole.

1. Pestov NB, Korneenko TV, Shakhparonov MI, Shull GE, Modyanov NN. (2006) Loss of acidification of anterior prostate fluids in Atp12a-null mutant mice indicates that nongastric H-K-ATPase functions as proton pump in vivo. Am J Physiol, Cell Physiol, 291 (2): C366-74. [PMID:16525125]