The pump responsible for gastric acid secretion is
H+ ATPase
Na+ - H+ ATPase
H+ - K+ ATPase
Ca2+ - H+ ATPase
Gastric parietal cells are highly specialized for their unusual task of secreting concentrated acid. The cells are packed with mitochondria that supply energy to drive the apical H+,K+-ATPase, or proton pump, that moves H+ ions out of the parietal cell against a concentration gradient. The apical membrane also contains potassium channels, which supply the K+ ions to be exchanged for H+, and Cl- channels that supply the counterion for HCl secretion.
Gastrointestinal System