Direct electrochemistry of redox proteins or enzymes at various film electrodes and their possible applications in monitoring some pollutants*

Water-insoluble films modified on the surface of solid electrodes may provide a unique microenvironment for electron transfer of some redox proteins or enzymes. The film materials can be two-tail surfactants, or composites of polyion-surfactant or clay-surfactant. Both surfactant and composite films cast on surface of electrodes are self-assembled into an ordered multibilayer structure, which is very similar to the bilayer structure of biological membrane. Amphiphilic polymers can also be used for making films. Incorporated heme proteins such as myoglobin (Mb), hemoglobin (Hb), or horseradish peroxidase (HRP) in these films demonstrated reversible voltammetry. Studies of direct electrochemistry of these proteins in various films by our group are reviewed in this paper. The protein films may provide a good model for study of electron transfer process in biological systems. The electrocatalytic properties of the protein films may also be applied to monitor some pollutant substrates.