Potassium-transporting ATPase subunit alpha 1 (ATP4A)

The Potassium-transporting ATPase subunit alpha 1, also known as the gastric H+/K+ ATPase alpha subunit, is the major catalytic component of the proton pump located in the parietal cells of the stomach (UniProt P20648). It functions as an electroneutral P-type ATPase, exchanging cytoplasmic protons for extracellular potassium ions through the hydrolysis of ATP to create the highly acidic environment of the gastric lumen (PubMed 11024021). This enzyme serves as the final common pathway for gastric acid secretion, making it a primary pharmacological target for treating acid-related gastrointestinal diseases like gastroesophageal reflux disease (GERD), peptic ulcer disease, and Zollinger-Ellison syndrome (StatPearls NBK499945). Therapeutic agents such as Proton Pump Inhibitors (PPIs) like omeprazole achieve acid suppression by forming covalent disulfide bonds with cysteine residues on this alpha subunit (PubChem CID 4594). More recently, Potassium-Competitive Acid Blockers (P-CABs) like vonoprazan have been developed to provide faster and more potent inhibition by competing for the potassium-binding site (PubMed 29070704). While highly effective, long-term suppression of this target is associated with safety concerns including hypomagnesemia, vitamin B12 deficiency, and an increased risk of enteric infections (NIH PMC6370232).

Other names

Gastric H+/K+ ATPase alpha subunitProton pumpH(+)/K(+) ATPase alpha subunitATP4AH-K-ATPase alpha subunit

Irreversible inhibition of the H+/K+ ATPase enzyme via covalent binding to cysteine residues (PPIs) or reversible, K+-competitive inhibition (P-CABs) to block the final step of gastric acid secretion.