Temperature dependence of the reduction potential of Cu sub(A) in carbon monoxide inhibited cytochrome c oxidase
The temperature dependence of the reduction potential of the Cu sub(A) 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...
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Published in | Biochemistry (Easton) Vol. 25; no. 1; pp. 167 - 171 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
01.01.1986
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Subjects | |
Online Access | Get full text |
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Summary: | The temperature dependence of the reduction potential of the Cu sub(A) 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 Fe sub(a), indicate that an interaction between Cu sub(A) and Fe sub(a) 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 Cu sub(A) reduction potential indicates a relatively large and negative standard entropy of reduction of Cu sub(A) ( Delta S degree ' = -48.7 plus or minus 2.3 eu). Possible implications of the intersite redox interaction and the large standard entropy of reduction of the Cu sub(A) site are discussed. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 content type line 23 ObjectType-Feature-2 |
ISSN: | 0006-2960 |