title: An electrogenic proton-translocating adenosine triphosphatase from bovine kidney medulla.
abstract: Urinary acidification in the mammalian collecting tubule is similar to that in the turtle bladder, an epithelium whose H+ secretion is due to a luminal proton-translocating ATPase. We isolated a fraction from bovine renal medulla, which contains ATP-dependent proton transport. H+ transport was found to be electrogenic in that its rate was reduced by a membrane potential. H+ transport activity was inhibited by N-ethyl maleimide and dicyclohexyl carbodiimide, but not by oligomycin or vanadate; its activity did not depend on the presence of potassium, differentiating this ATPase from the mitochondrial F0-F1 ATPase and the gastric H+-K+ ATPase. H+ transport activity had a specific substrate requirement for ATP, distinguishing this pump from the lysosomal H+ ATPase, which uses guanosine or inosine triphosphate as well. The distribution of this H+ pump on linear sucrose density gradient was different from that of markers of lysosomes and basolateral membranes. These results show that the kidney medulla contains an H+ -translocating ATPase different from mitochondrial, gastric, and lysosomal proton pumps, but similar to the turtle bladder ATPase.
mesh_terms: D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D002417:Cattle; D005033:Ethylmaleimide / Q000494:pharmacology; D007672:Kidney Cortex / Q000201:enzymology; D007679:Kidney Medulla / Q000201:enzymology*; D007700:Kinetics; D009840:Oligomycins / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013367:Submitochondrial Particles / Q000201:enzymology; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D009840:Oligomycins; D010743:Phospholipids; D013385:Succinate Dehydrogenase; D000118:Acetylglucosaminidase; D006180:Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D005033:Ethylmaleimide