CALCULATION OF THE CYTOCHROME-P-450 REDOX POTENTIAL FROM KINETIC DATA BY THE MARCUS TREATMENT - FEASIBLE OR NOT

Using calculations based on the Marcus theory (or linear approximations thereof) and existing rate constant/oxidation potential data, an attempt has been made to estimate the effective standard potential and reorganization energy of the P-450/(P-450)-.couple. Due to the limited data basis, the results only qualitatively indicate that P-450 either must possess an extremely high Eo'Fe(V)/Fe(IV) value (greater than 2.5 V!) or not act as an electron transfer oxidant at all. By similar calculations, it was found that model alkene epoxidation reactions do not follow an ET mechanism.