This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Pharmacology
Proton pump inhibitors inhibit_____ in the parietal cells of stomach - 
Select and explain. 
A. H+ K ATPase, B. Na Ca ATPase, C. Ligand gated K channel, D. Ligand gated Ca channel
A: H+ K ATPase
Answer: A: H+ K ATPase 
Explanation: Ans. is 'a' i.e., H+ K ATPase * Drugs in this group are - Omeprazole, Esomeprazole, Lansoprazole, Pantoprazole, Rabeprazole.* These drugs inhibit H+ K+ ATPase in parietal cells of stomach.