Mechanisms of Electron Transfer in Cytochromes and Blue Copper Proteins

Author: Coyle, Catherine Louise

Year: 1978

Degree: Dissertation (Ph.D.)

Advisor: Gray, Harry B.

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/fq3x-yd79

Abstract

The mechanisms of electron transfer in cytochromes and bluecopper proteins are investigated by examining the oxidation and reduction of horse heart cytochrome c, Pseudomonas aeruginosa cytochrome c₅₅₁, Rhus vernicifera stellacyanin, Phaseolus vulgaris plastocyanin and Pseudomonas aeruginosa azurin by inorganic redox agents. The rates of electron transfer in these systems have been analyzed within the framework of the relative Marcus theory of outer sphere electron transfer. The activation parameters for these processes have also been examined.

The reduction of Pseudomonas aeruginosa cytochrome c₅₅₁, by Fe(EDTA)^2- has been investigated. The electrostatics-corrected self-exchange rate constant is similar to that obtained for horse heart cytochrome c. The close correspondence indicates that the two proteins employ similar electron transfer mechanisms. It is proposed that this mechanism. involves reagent contact and little protein conformational change at the partially exposed heme edge.

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