The thermodynamics and kinetics of electron transfer in the cytochrome P450cam enzyme system.
In anaerobic environments the first electron transfer in substrate-free P450cam is known to be thermodynamically unfavourable, but in the presence of dioxygen the reduction potential for the reaction shifts positively to make electron transfer thermodynamically favourable. Nevertheless a slower rate of electron transfer is observed in the substrate-free P450cam compared to substrate-bound P450cam. The ferric haem centre in substrate-free P450cam changes from six co-ordinate to five co-ordinate when reduced whereas in substrate-bound P450cam the iron centre remains five co-ordinate in both oxidation states. The slower rate of electron transfer in the substrate-free P450cam is therefore attributed to a larger reorganisation energy as predicted by Marcus theory.
Honeychurch
M J
MJ
Inorganic Chemistry Laboratory, Oxford, UK.
Hill
A O
AO
Wong
L L
LL
D000818:Animals; D019475:Camphor 5-Monooxygenase / Q000737:chemistry* / Q000378:metabolism*; D004579:Electron Transport; D006801:Humans; D007700:Kinetics; D013816:Thermodynamics
D019475:Camphor 5-Monooxygenase