Potassium-transporting ATPase (gastric proton pump) (H⁺/K⁺-ATPase)

The potassium-transporting ATPase (H⁺/K⁺-ATPase), also known as the gastric proton pump, is the enzyme responsible for the final step in gastric acid secretion in the stomach. It is located in the membrane of parietal cells[4][5]. This pump exchanges intracellular hydrogen ions (H⁺) for extracellular potassium ions (K⁺), actively secreting hydrochloric acid into the gastric lumen. Gastric acid production is tightly regulated by neuronal, hormonal, and paracrine pathways: acetylcholine (from vagus nerve endings), gastrin (from G cells), and histamine (from ECL cells) stimulate acid secretion, while somatostatin inhibits it[1][2][3][4][5]. The pump is the principal therapeutic target in the treatment of acid-related diseases such as GERD and peptic ulcers. Proton pump inhibitors irreversibly block the enzyme, profoundly suppressing gastric acid production and facilitating healing of the gastric mucosa[4].

Other names

Gastric proton pumpGastric H⁺/K⁺-ATPaseProton pumpGastric acid pump

Covalent inhibition of the gastric proton pump (PPIs bind to cysteine residues on the ATPase, irreversibly blocking its action)[4] Reversible inhibition of pump activity (potassium-competitive acid blockers)