A scanning tunnelling study of immobilised cytochrome P450(cam)

A site-specifically engineered surface cysteine residue, located in a regio n where the haem moiety is closest to the surface, is used to anchor cytoch rome P450(cam) enzyme molecules covalently to a gold electrode. More reprod ucibly ordered adsorption, at high coverage, occurs with this K344C mutant than with the wild-type enzyme. The subsequently formed close-packed monola yer arrays have been probed by scanning tunnelling microscopy under ambient conditions and under aqueous (buffered) solution at high resolution. Initi al indications suggest that the immobilised enzyme is both electrochemicall y addressable and catalytically active.