Protein-Surfactant Film Voltammetry of Wild-Type and Mutant Cytochrome P450 BM3
We are investigating the redox chemistry of wild-type (WT) and mutant (1-12G) cytochrome P450 BM3. Absorption spectra in solution feature the FeIII Soret at 418 nm for WT and a split Soret for 1-12G at 390 and 418 nm. Voltammetry of the proteins within DDAPSS films on the surface of carbon electrodes reveal nearly identical FeIII/II potentials (approximately −200 mV vs Ag/AgCl), but significant differences in k°, 250 vs 30 s-1, and FeIII/II−CO potentials, −140 vs −115 mV, for WT vs 1-12G. Catalytic reduction of dioxygen by the proteins on rotating-disk electrodes was analyzed using Levich and Koutecky−Levich treatments. The data reveal 1-12G n and kobs values that are, respectively, 1.7 and 0.07 times those of WT, suggesting that the two proteins differ strikingly in their reactions with dioxygen.
Andrew K. Udit, Nareen Hindoyan, Michael G. Hill, Frances H. Arnold, and Harry B. Gray. "Protein-Surfactant Film Voltammetry of Wild-Type and Mutant Cytochrome P450 BM3" Inorganic Chemistry 44.12 (2005): 4109-4111.