The K+-transporting ATPase mediates the exchange of potassium and hydrogen ions Authored: Jassal, B, 2010-08-26 EC Number: 3.6.3.10 Edited: Jassal, B, 2010-08-26 Pubmed1656976 Pubmed2160952 Pubmed8045293 Reactome Database ID Release 43937311 Reactome, http://www.reactome.org ReactomeREACT_25173 Reviewed: He, L, 2010-11-15 The potassium-transporting ATPase heterodimer catalyzes the hydrolysis of ATP coupled with the exchange of H+ and K+ ions across the plasma membrane. It is composed of alpha and beta chains. Two human genes encode the catalytic alpha subunit, ATP4A and ATP12A (Maeda et al, 1990; Grishin et al, 1994). ATP4A is responsible for acid production in the stomach. <br>ATP12A is responsible for potassium absorption in various tissues. One human gene encodes the beta subunit, ATP4B (Ma et al, 1991).