Thermodynamic and spectroscopic characteristics of the cytochrome bc1 complex. Role of quinone in the behavior of cytochrome b562

J. C. Salerno, Y. Xu, M. P. Osgood, C. H. Kim, T. E. King

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Cytochrome b562 does not behave as a single independent thermodynamic component in preparations of purified quinol cytochrome c reductase. This effect is much more pronounced in quinone sufficient preparations; in such preparations, the epr spectrum of the cytochrome is E(h) sensitive, with a peak shift from g = 3.42 to 3.48 occurring as the potential is lowered from 100 mV to 0 mV. The peak shift is dependent on the presence of quinone and can be restored to quinone-depleted preparations by supplementation with ubiquinol 2 if phospholipid depletion is not too severe. The results suggest that cytochrome b562 is strongly interacting with the Qc quinone binding site.

Original languageEnglish (US)
Pages (from-to)15398-15403
Number of pages6
JournalJournal of Biological Chemistry
Issue number26
StatePublished - Jan 1 1989


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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