Hybrid protein films incorporating Cyt-c immobilized on TiO₂ films were prepared and characterised optically with UV-visible spectroscopy and electrochemically with cyclic voltammetry, and their conductivity properties were studied in detail. In addition the effects of a thin overlayer coating of a second metal oxide such as SiO₂, Al₂O₃, ZrO₂ and MgO₂ were studied and the effects over the electrochemical properties of the hybrid working electrodes were discussed.