H,K-ATPase and Acid Secretion Control in Gastric Mucosa

O. D. Lopina^1,2 and A. M. Rubtsov¹

¹Department of Biochemistry, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (7-095) 939-3955; E-mail: odl@atpase.bio.msu.su

²To whom correspondence should be addressed.

Submitted March 28, 1997; revision submitted June 8, 1997.

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H,K-ATPase from gastric mucosa is responsible for HCl secretion in the gastric lumen and is a member of the P-type ATPase family. The structure of enzyme subunits, their functions and topology, the mechanism of ATP hydrolysis and transport function of the enzyme, its specific inhibitors, and the success of their pharmacological application are reviewed. The methods for isolation of membrane fractions with H,K-ATPase activity and attempts for solubilization and purification of the enzyme are described. Data demonstrating the presence of H,K-ATPase in other tissues are considered. Information about other enzyme systems of parietal cells involved in transepithelial transport of HCl (the Cl- and K-channels of the apical membrane, the HCO₃^-/Cl^- anion exchanger and Na⁺/H⁺ cation exchanger of the basolateral membrane) is presented. Mechanisms of activation of acid secretion by parietal cells via gastrin, acetylcholine, and histamine receptors and the role of cytoskeletal proteins in activation are reviewed.

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KEY WORDS: H,K-ATPase, HCl secretion, gastric mucosa, parietal cells, gastrin, acetylcholine, histamine.

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