ATP-driven proton fluxes across membranes of secretory organelles.
The ATP-dependent proton uptake by chromaffin granule membranes, lysosomes, and synaptosomes was examined. In synaptosomes the reaction was absolutely dependent on the presence of chloride, while in chromaffin granules chloride had a profound effect and in lysosomes only a minor effect. The presence of chloride markedly increases the rate of collapse of delta pH by carbonyl cyanide p-trifluoromethoxyphenylhydrazone in all three organelles. Ascorbate with phenazine methosulfate uncoupled the ATP-dependent proton uptake by chromaffin granules, but had no effect on lysosomes and synaptosomes. Proton uptake by submitochondrial particles was about 50-fold more sensitive to dicyclohexylcarbodiimide than the proton uptake by chromaffin granule membranes. Chromaffin granule membranes were treated with 2 M sodium bromide to inactivate the mitochondrial ATPase. The treatment caused a complete inhibition of the ATP-dependent proton uptake. Solubilization of these membranes by sodium cholate, followed by reconstitution by cholate dilution revealed the ATP-dependent proton uptake of the system. It is concluded that the genuine ATPase enzyme of chromaffin granules is a proton translocator.
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000313:Adrenal Medulla / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001921:Brain / Q000378:metabolism; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D005260:Female; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013367:Submitochondrial Particles / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*; D014634:Valinomycin / Q000494:pharmacology
D014634:Valinomycin; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D011189:Potassium Chloride; D000255:Adenosine Triphosphate