Modulation of the electrophoretic ATP-induced K(+)-transport in yeast mitochondria by delta pH.
The modulation of the ATP-induced K(+)-transport pathway of the yeast inner mitochondrial membrane by delta pH was investigated in two ways. First, the inhibitory effect of phosphate was compared to the effect of other permeant acids, demonstrating that a part of the effect of phosphate was linked to its electroneutral transport down delta pH. However, an additional effect specific for phosphate also occurred inside the matrix. Second, the stimulation of the respiration by ATP in the presence of K+ was compared to the effects of the protonophore ClCCP2 and of the K(+)-ionophore valinomycin. Quite unexpectedly, the effect of ATP looked more like the effect of ClCCP than the effect of valinomycin. This and previous results (Manon et al., Biochimica et Biophysica Acta 1231, 282-288 (1995)) show that the rate of electrophoretic K(+)-entry is limited by the rate of electroneutral K(+)-exit via the K+/H+ exchange and is therefore delta pH-dependent.
Roucou
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X
Institut de Biochimie et de Génétique Cellulaires du Centre National de la Recherche Scientifique, Université Victor Ségalen-Bordeaux II, France.
Manon
S
S
Guérin
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M
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000031:analogs & derivatives / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects; D007476:Ionophores / Q000494:pharmacology; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D010710:Phosphates / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D014634:Valinomycin / Q000494:pharmacology
D002712:Chlorides; D007476:Ionophores; D010710:Phosphates; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000255:Adenosine Triphosphate; D011188:Potassium