DIRECT ELECTRON INJECTION FROM ELECTRODES TO CYTOCHROME P450(CAM) IN BIOMEMBRANE-LIKE FILMS

Direct, reversible, electron transfer has been demonstrated between el ectrodes and native cytochrome P450(cam) (cyt P450(cam)) in lipid film s. Electron injection directly from electrodes into the haem Fe-III of cyt P450(cam) has been confirmed by the influence of the known reacti on of cyt P450(cam)Fe(II) with CO on the voltammetric midpoint potenti al. Analysis of square wave voltammograms suggested a distribution of enzyme formal potentials in the films. With oxygen present, more than one electron was injected into the enzyme in films, mimicking in vivo electron acceptance by cyt P450Fe(III) and cyt P450Fe(II)-O-2 during c atalytic oxidations. Cyt P450(cam) films also catalysed electrochemica lly driven reduction of trichloroacetic acid in anaerobic solutions. T hese stable enzyme-lipid films may find applications in fundamental bi ochemical and toxicity studies, biocatalysis and biosensors.