[1][2][3][4] P450 enzymes usually function as a terminal oxidase in multicomponent electron-transfer chains, called P450-containing monooxygenase systems, although self-sufficient, non-monooxygenase P450s have been also described.
In bacteria, putidaredoxin, terpredoxin, and rhodocoxin serve as electron carriers between corresponding NADH-dependent ferredoxin reductases and soluble P450s (CYP101, CYP108, CYP116).
The general scheme of electron flow in the CPR/P450 system is: The ubiquitous electron-transport protein cytochrome b5 can serve as an effector (activator or inhibitor) of P450s.
The general scheme of electron flow in this system appears to be: Nitric oxide reductase (P450nor) is a P450 enzyme involved in denitrification in several fungal species.
Substrates for all these enzymes are fatty acid derivatives containing partially reduced dioxygen (either hydroperoxy or epidioxy groups).