Aspects of Gastric Proton-Transport ATPase

The central role of H+ transport in a variety of biological membranes has been firmly established by experiments of the last decade or so (Mitchell, 1966; Racker, 1976). Of direct interest to this review is the mechanism of proton transport by the mammalian gastric mucosa, a tissue where the H+ gradient reaches a value of almost 107. Whether the mechanism in this cell has anything in common with other H+ ion transport systems is not clear at present. It does seem that at least part of the process is mechanistically similar to the mechanism of Na+ and K+ transport in eukaryotic cells via the Na+/K+-ATPase (Taniguchi and Post, 1975) and hence is likely to be of general as well as special interest. At this time the only well-defined component of acidification is the H+/K+-ATPase initially described by Forte and his collaborators (Ganser and Forte, 1973a). It is this enzyme, and the evidence for its role in acid secretion that will be described in this brief review.