Source:http://linkedlifedata.com/resource/umls/id/C0771765
NCI: The magnesium salt form of a benzimidazole with selective and irreversible proton pump inhibitor activity. In the acidic compartment of parietal cells, omeprazole is protonated and converted into the active achiral sulfenamide; the active sulfenamide forms one or more covalent disulfide bonds with the proton pump hydrogen-potassium adenosine triphosphatase (H+/K+ ATPase), thereby inhibiting its activity and the parietal cell secretion of H+ ions into the gastric lumen, the final step in gastric acid production. H+/K+ ATPase is an integral membrane protein of the gastric parietal cell.