Reversible potentials (Eac0) of the surface confined Fe^3+/2+ redox couple derived from the a.c. voltammograms (<i>f</i> = 219 Hz)<i>^{^a}</i> obtained from CNT electrodes modified with hemin, wt cyt b5, E48G/E49G cyt b5, P450c17, and their combinations.

a Average of the potentials of the central minimum in the 6th a.c. harmonic (envelope presentation, in Fig 3) from the forward and backward d.c. potential sweep directions. b Values are reproducible to ±0.001 V. c Hemin adsorbed on the electrode pre-modified with wt cyt b5. d either wt or E48G/E49G cyt b5 adsorbed on the electrode pre-modified with P450c17. Reversible potentials (Eac0) of the surface confined Fe3+/2+ redox couple derived from the a.c. voltammograms (f = 219 Hz)a obtained from CNT electrodes modified with hemin, wt cyt b5, E48G/E49G cyt b5, P450c17, and their combinations.