Temperature Dependence of the Reduction Potential of CuA in Carbon Monoxide Inhibited Cytochrome c Oxidase

Hsin Wang, David F. Blair, Walther R. Ellis, Harry B. Gray, Sunney I. Chan

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

The temperature dependence of the reduction potential of the CuA site in carbon monoxide inhibited cytochrome c oxidase has been measured with a spectroelectrochemical method adapted to the relatively weak near-infrared absorption of this copper ion. These measurements, together with parallel measurements on the 604-nm absorption due to Fea, indicate that an interaction between CuA and Fea causes the reduction potential for one of these sites to be decreased by approximately 40 mV upon reduction of the other. The temperature dependence of the CuA reduction potential indicates a relatively large and negative standard entropy of reduction of CuA(ΔS°' = -48.7 ± 2.3 eu). Possible implications of the intersite redox interaction and the large standard entropy of reduction of the CuA site are discussed.

Original languageEnglish (US)
Pages (from-to)167-171
Number of pages5
JournalBiochemistry
Volume25
Issue number1
DOIs
StatePublished - Jan 1986
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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