Electron Transfer Reactions Between Cytochrome c, Cytochrome c Oxidase and Dioxygen

Virginia Commonwealth University, Richmond VA

Investigators

Abstract

This project, which is supported in the Analytical and Surface Chemistry program develops new electrochemical methods for studying membrane-bound enzymes in complex media. Conducted by Dr. Albert Sneden and his group at Virginia Commonwealth University, the project prepares and characterizes stable assemblies of cytochrome c oxidase (CCO) adsorbed on a lipid bilayer that is anchored into a silver-coated gold electrode. A quartz crystal microbabance is used to coat the electrode with an optimum layer of silver. The electrode is then covered with octadectyl mercaptan to form an anchor for the bilayer. Atomic Force Microscopy is used to confirm the structure of the membrane. Electrochemical experiments have confirmed that such a bilayer mimics the in vivo reactivities of CCO. The known reaction between cyanide and CCO forms the basis for these studies. The electron transfer reaction between reduced cytochrome under flow conditions, CCO in the bilayer, and the electrode is characterized as a function of cyanide concentration, steady state turnover rate, and oxygen concentration. This research develops new electrochemical methods for studying membrane-bound enzymes in complex media. Results from this research will be useful for assessing the potential efficacy of compounds as enzyme inhibitors and will be important in areas such as drug testing.