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J Bioenerg Biomembr. 1993 Apr;25(2):115-20.

The sequence of electron carriers in the reaction of cytochrome c oxidase with oxygen.

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Department of Biological Sciences, University of Calgary, AB, Canada.


Kinetic studies of the electron transfer processes performed by cytochrome oxidase have assigned rates of electron transfer between the metal centers involved in the oxidation of ferrocytochrome c by molecular oxygen. Transient-state studies of the reaction with oxygen have led to the proposal of a sequence of carriers from cytochrome c, to CuA, to cytochrome a, and then to the binuclear (i.e., cytochrome a3-CuB) center. Electron exchange rates between these centers agree with relative center-to-center distances as follows; cytochrome c to CuA 5-7 A, cytochrome c to cytochrome a 20-25 A, CuA to cytochrome a 14-16 A and cytochrome a to cytochrome a3-CuB 8-10 A. It is proposed that the step from cytochrome a to the binuclear center is the key control point in the reaction and that this step is one of the major points of energy transduction in the reaction cycle.

[Indexed for MEDLINE]

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