The relationship between the redox reaction of camphor‐induced cytochrome p‐450 and its activity

The relationship between the redox reaction of camphor‐induced cytochrome P‐450 (P‐450_cam) and its activity was measured by using cyclic voltammetry. The redox potential of P‐450_cam solution shifted to the lower side of the potential by binding of substrate, and the change was proportional to the amount of the substrate binding to the protein. The substrate binding was inhibited at the low concentration of oxygen in the reaction solution. The reaction product, hydroxycamphor, was observed in the reaction mixture by gas chromatography/mass spectroscopy. However, hydroxycamphor was not observed at an oxygen concentration of about a tenth part of the saturated one. The shift of redox potential of P‐450_cam solution corresponded to the substrate specificity of the activity. These results suggest that the redox reaction of P‐450_cam related to the substrate‐binding to the protein and its activity. Furthermore, the present system was very simple and speedy for the measurement of the activity. Copyright © 1999 John Wiley & Sons, Ltd.