title: Protein-surfactant film voltammetry of wild-type and mutant cytochrome P450 BM3.
abstract: We are investigating the redox chemistry of wild-type (WT) and mutant (1-12G) cytochrome P450 BM3. Absorption spectra in solution feature the Fe(III) 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 Fe(III/II) potentials (approximately -200 mV vs Ag/AgCl), but significant differences in k degrees , 250 vs 30 s(-)(1), and Fe(III/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 k(obs) 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.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Udit
authors.forename: Nareen
authors.initials: N
authors.lastname: Hindoyan
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hill
authors.forename: Frances H
authors.initials: FH
authors.lastname: Arnold
authors.forename: Harry B
authors.initials: HB
authors.lastname: Gray
mesh_terms: D002384:Catalysis; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000235:genetics; D004563:Electrochemistry; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D010084:Oxidation-Reduction; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins; D003577:Cytochrome P-450 Enzyme System; D007501:Iron