Quantitative analysis of proton movements associated with the uptake of weak carboxylic acids. The yeast Candida utilis as a model.
A quantitative analysis of the proton movements associated with the initial uptake rate of weak short-chain carboxylic acids was developed in order to estimate proton/carboxylate symports stoichiometries. The yeast Candida utilis was used as a biological model and the deduced equations were applied on the elucidation of the proton/carboxylate symports stoichiometries of lactate, succinate and citrate in a strain of that yeast species at different pH values. At pH 5.0, the proton/lactate and the proton/succinate symport stoichiometry was 1:1. In the cases of the proton/lactate and proton/citrate symports it appears that the stoichiometry ratio increased with increasing extracellular pH.
Cássio
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F
Laboratory of Biology, University of Minho, Braga, Portugal.
Côrte-Real
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M
Leão
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C
D001692:Biological Transport; D002175:Candida; D002264:Carboxylic Acids / Q000737:chemistry / Q000378:metabolism*; D003998:Dicarboxylic Acids / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008433:Mathematics; D008962:Models, Theoretical; D011522:Protons; D014233:Tricarboxylic Acids / Q000378:metabolism
D002264:Carboxylic Acids; D003998:Dicarboxylic Acids; D011522:Protons; D014233:Tricarboxylic Acids