Electrogenicity of the lysosomal proton pump.
Using acridine orange as a pH gradient probe, the effects of valinomycin and FCCP on the pH gradient across lysosomal membranes in an ATP-free medium as well as on the rate of the inward ATP-driven proton translocation were investigated. Both lysosome-enriched and highly purified lysosomal preparations from rat liver were used with identical results. Ionophore effects were found to be different depending upon whether passive ion fluxes or ATP-driven H+ translocation were involved and supported the existence of a membrane potential in the latter case. Anions stimulated the rate of ATP-driven proton translocation and stimulation increased with increasing anion lipophilicity. These results strongly support the electrogenic nature of the lysosomal proton pump.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D014634:Valinomycin / Q000494:pharmacology
D014634:Valinomycin; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D000255:Adenosine Triphosphate