H+ transport and membrane-bound HCO - 3 ATPase in salivary duct epithelium.
An ATPase stimulated by HCO -  ions and other oxybases and inhibited by SCN- has been found in main excretory duct of rat submaxillary gland, a tissue, capable of actively secreting HCO - 3 ions. No such ATPase was found in the rabbit duct, which normally does not secrete HCO - 3. The HCO - 3 ATPase was localized in the plasma membrane fraction of the homogenate, as evidenced by the marker 5'-nucleotidase. The activities of the HCO - 3 ATPase increased in metabolic alkalosis and decreased in metabolic acidosis in parallel to secretion of HCO - 3 and K+ ions by the duct epithelium. These findings provide further evidence that the membrane-bound HCO - 3 ATPase is involved in active H+/HCO - 3 transport.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism*; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000201:enzymology; D004848:Epithelium / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008861:Microsomes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D013363:Submandibular Gland / Q000201:enzymology* / Q000378:metabolism
D001639:Bicarbonates; D006859:Hydrogen; D000251:Adenosine Triphosphatases; D011188:Potassium