Clathrin-coated vesicles from rat liver: enzymatic profile and characterization of ATP-dependent proton transport.
Clathrin-coated vesicles isolated from rat liver exhibited an enzymatic profile distinct from that of rat liver plasma membranes, lysosomes, microsomes, and mitochondria. The coated vesicles catalyzed ATP-dependent proton transport that acidified the vesicle interior, as measured by the fluorescence quenching of acridine orange. H+ transport by coated vesicles was not inhibited by vanadate (0.1 mM) or ouabain (2 mM) and differed from H+ transport by rat liver submitochondrial particles in its greater resistance to inhibition by oligomycin (10 pM to 10 microM) and N,N'-dicyclohexylcarbodiimide (DCCD) (0.1-100 microM) and its sensitivity to N-ethylmaleimide (0.1-2 mM). H+ transport was stimulated by valinomycin in the presence of K+, exhibited no specific cation requirement, but was dependent upon the presence of a permeant anion, with Cl- and Br- being the most effective of the anions studied. Finally, H+ transport was poorly supported by GTP, UTP, or ADP and exhibited no consistent relationship to the coated vesicle-associated ouabain-insensitive ATPase activity.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D002458:Cell Fractionation / Q000379:methods; D002966:Clathrin / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000201:enzymology* / Q000648:ultrastructure; D011992:Endosomes / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008930:Mitochondria, Liver / Q000201:enzymology; D010088:Oxidoreductases / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013367:Submitochondrial Particles / Q000201:enzymology
D002966:Clathrin; D010088:Oxidoreductases; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D006180:Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase