Na+/H+ exchange in mitochondria as monitored by BCECF fluorescence

András Kapus, Erzsébet Ligeti, Attila Fonyó

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16 Citations (Scopus)

Abstract

The recently developed method of loading isolated heart mitochondria with the fluorescent pH indicator, BCECF, was applied to monitor the Na+0/H+i exchange process from the matrix side of the membrane. The Na+-induced changes in the pH of the matrix (pHm) showed that: (i) the Na+0/H+i exchange followed Michaelis-Menten kinetics with respect to external Na+ with a Km of approx. 20 mM; (ii) in contrast to this, the dependence of the exchange rate on the matrix [H+] did not obey the Michaelian model. No Na+-induced alkalinization occurred above a pHm of 7.45±0.09 (n=4). Below this value the reciprocal of the transport rate and that of the matrix [H+] deviated upwardly from the straight line. The results suggest that internal H+ might exert allosteric control on the mitochondrial Na+/H+ exchange process.

Original languageEnglish
Pages (from-to)49-52
Number of pages4
JournalFEBS letters
Volume251
Issue number1-2
DOIs
Publication statusPublished - Jul 17 1989

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Keywords

  • (Mitochondria)
  • Biscarboxyethylcarboxyfluorescein
  • Matrix pH
  • Na/H exchange

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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