title: Characterization of the ouabain-insensitive ATPase activity of rat liver plasma membranes.
abstract: Very little is currently known about the ouabain-insensitive ATPase activity of the liver plasma membrane; we have therefore characterized it in plasma membranes from rat liver prepared using two different isolation techniques. Greater than 85% of ATPase activity in both preparations was ouabain-insensitive. Based on the effects of multiple inhibitors, including dicyclohexylcarbodiimide (DCCD), N-ethylmaleimide (NEM), vanadate, and oligomycin, the ouabain-insensitive ATPase activity of rat liver plasma membranes consists of a family of ATP-hydrolysing enzymes. Ouabain-insensitive ATPase activity was stimulated by HCO3-in both plasma membranes (13%) and mitochondria (69%) over the range of 7.5 to 9.0, and HCO3--stimulation was similarly inhibited by oligomycin in both preparations. A fraction of the ouabain-insensitive ATPase of liver plasma membranes is inhibited by DCCD and is resistent to inhibition by oligomycin; these characteristics are similar to those of the non-mitochondrial H+-ATPases recently described in lysosomes, endosomes, clathrin-coated vesicles, and Golgi from liver and other cell types.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D002712:Chlorides / Q000494:pharmacology; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008297:Male; D009840:Oligomycins / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000494:pharmacology; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology
chemical_list: D001639:Bicarbonates; D002712:Chlorides; D009840:Oligomycins; D014639:Vanadium; D014638:Vanadates; D004024:Dicyclohexylcarbodiimide; D010042:Ouabain; D012964:Sodium; D000251:Adenosine Triphosphatases; D005033:Ethylmaleimide; D011188:Potassium