Effect of pH on the transport of Krebs cycle intermediates in renal brush border membranes

Stephen H. Wright, Ian Kippen, Ernest M. Wright

Research output: Contribution to journalArticle

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Abstract

Lowering extravesicular pH stimulated Na+-dependent citrate transport in renal brush border membrane vesicles: e.g., at pHout = 5.5, the initial rate of citrate uptake was increased 10-fold compared to parallel control experiments at pH 7.5. The same experimental conditions had little effect on succinate uptake. The influence of pH on citrate transport is a product of the extravesicular H+ concentration; pH gradients did not potentiate the effects nor were proton gradients capable of driving transport in the absence of Na+. The effect of pH is adequately explained if only the mono- and divalent species of citrate (Cit1-, Cit2-) are considered acceptable substrates for transport. The stimulatory influence of pH on transport correlated quite well with pH-related increases in the concentrations of Cit1- and Cit2-, and over the same pH range [Cit3-] was inversely related to citrate uptake. A model of the Na+-dependent dicarboxylate transport system is discussed in which three sodium ions are translocated per molecule of dicarboxylic acid.

Original languageEnglish (US)
Pages (from-to)287-290
Number of pages4
JournalBBA - Biomembranes
Volume684
Issue number2
DOIs
StatePublished - Jan 22 1982

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Keywords

  • (Rabbit kidney)
  • Brush border membrane
  • Citrate transport
  • Tricarboxylic acid cycle
  • pH effect

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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