User:Alisha, Deepa, Pamiz/Sandbox 1: Difference between revisions

The H+/K+-ATPase pump is part of the P-type ATPase family located within the cytoplasmic membrane of resting parietal cells (Figure 1); powered through ATP hydrolysis, the ATPase is translocated to the canalicular membrane and begins to pump cytoplasmic H+ into the canalicular space, in exchange for extracellular K+ ions. It is a pro-drug that is protonated twice in the acidic environment of the parietal cell to form the active inhibitor, sulfenamide which forms disulfide bonds with Cys 813 and Cys 892 on the α subunit of the H+/K+-ATPase.3 Targeting this enzyme using PPIs is the most effective therapeutic control agent of gastric acid secretion.3 Esomeprazole is an α,β-heterodimeric enzyme, where the catalytic site is present in the α subunit(Figure 2).7 Transmembrane segments TM4, TM5, TM6, and TM8, are located in the α subunit and contain the ion binding region of the enzyme.7 Binding of ions and ATP to these domains will induce movements in the membrane domain that catalyze ion displacement.7