Proton Pump

Proton pump inhibitors block the gastric hydrogen/potassium pump (H+/K+-ATPase) that acidifies the stomach. In 1981 substituted benzimidazoles were shown to inhibit gastric acid secretion by blocking this enzyme. These compounds are prodrugs that accumulate in the acidic secretory canaliculi and convert to reactive sulfenamides. The activated species bind cysteine residues of the pump covalently, which stops proton export until new enzyme is made. Benzimidazole inhibitors here include omeprazole, its S-enantiomer esomeprazole magnesium, lansoprazole and pantoprazole. Tenatoprazole is an imidazopyridine analog with a longer plasma half-life. The category also lists M2 ion channel blocker, a compound acting on the influenza A virus M2 proton channel.