Hoek 1970 Biochim Biophys Acta

Hoek JB, Lofrumento NE, Meyer AJ, Tager JM (1970) Phosphate transport in rat-liver mitochondria. Biochim Biophys Acta 226:297-308.

» PMID 5575160

Hoek JB, Lofrumento NE, Meyer AJ, Tager JM (1970) Biochim Biophys Acta

Abstract: 1. The kinetics of the efflux of Pi and malate as well as the relationship between Pi transport and intra- and extramitochondrial pH changes were studied in rat-liver mitochondria in the presence of rotenone and oligomycin at different pH's.

2. At high pH a fast efflux of Pi from the mitochondria occurs in the first few seconds, followed by a slow re-entry of Pi into the mitochondria. Under the same conditions the exit of malate shows a time lag of 2–4 sec. The exit of malate coincides with the re-entry of Pi.

3. In the presence of butylmalonate the exit of endogenous Pi is coupled with a concomitant alkalinization of the mitochondrial matrix space, as calculated from the distribution of 5,5-[14C]dimethyloxazolidine-2,4-dione.

4. The stoicheiometry of the Pi-hydroxyl exchange was found to be 1:1.

5. The kinetics of Pi transport are consistent with previous observations that there is a direct exchange between OH− and Pi, but not between OH− and malate. The equilibrium distribution of H2PO4− and OH− deviates from the Donnan distribution. This may be explained by assuming a pH-dependent binding of Pi in the mitochondria.

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• Komlódi et al (2022) The protonmotive force - not merely membrane potential. MitoFit Preprints 2022 (in prep)
  

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