A Study of Cytochrome c Oxidase in Lipid Bilayer Membranes on Electrode Surfaces

Abstract

A membraneassociated enzyme, cytochrome c oxidase, has been put in lipid bilayer membranes attached to gold electrode surfaces. Goldhhiol self-assembly chemistry and deoxycholate dialysis procedures have been used to insert cytochrome c oxidase into a lipid bilayer on gold surfaces with a controlled orientation. Voltammetric and spectroelectrochemical results indicate that direct electron-transfer communication between the gold electrode surface and cytochrome c oxidase has been achieved. Moreover, immobilized cytochrome c oxidase can both reduce and oxidize solution-resident cytochrome c by appropriately controlling the applied electrode potential.

Recent advances in the electrochemistry and spectroelectrochemistry of membrane proteins

“…The reconstitution of the enzyme in the phospholipid membrane was performed by detergent dilution of concentrated solutions of the enzyme. At almost the same time, the same protein was incorporated into a hybrid lipid bilayer assembled on a gold electrode (Cullison et al , 1994 ). In this study, the gold surface was first modified with a submonolayer of octadecyl mercaptan, and a deoxycholate dialysis procedure was used to add the second layer and incorporate the oxidase.…”

“…Cco reconstituted either within a supported lipid bilayer on an ITO electrode (Salamon et al , 1993 ) or within a hybrid bilayer assembled on a gold electrode (Cullison et al , 1994 ) also exhibited a DET. The values of the redox potentials suggest a communication with the Cu A and cyt-a 3 cofactors respectively.…”

4 Electrochemistry of Biomimetic Membranes

“…It catalyzes the redox reaction between the small peripheral protein cytochrome c in its reduced form, i.e., ferro-cytochrome c, and oxygen, with formation of ferri-cytochrome c and water; it also pumps protons from the matrix to the intermembrane space, where it interacts with ferrocytochrome c. COX was reported to retain its functional redox activity after incorporation in a gold-supported hybrid octadecanethiol/lipid bilayer from its detergent solution. 85 Thus, the cyclic voltammogram of COX in this hybrid bilayer yields an oxidation and a reduction peak whose peak potentials are practically equidistant from the known standard potential of the cytochrome a 3 redox site of this enzyme. However, this result was obtained by choosing thiol concentrations and experimental conditions allowing the formation of large uncovered areas of the gold electrode, where COX could partition into the hybrid bilayer during the dialysis procedure.…”

Fundamentals and Applications of Biological Redox Molecules and Nanocarbons Based on Electrochemical and Spectroelectrochemical Methods

“…4) We emphasize that molecular lipid-bilayer membranes on electrodes provide a microenvironment for facile electron transfer of redox proteins and enzymes. namely, we presented a concept (Fig.…”