The reducing equivalents from NADPH are transferred to P450 enzymes from two types of redox partners:

(a) for microsomal P450s, from NADPH cytochrome P450 reductase , with in some cases a contribution from cytochrome b5

and

(b) for mitochondrial P450s, from insect orthologs of adrenodoxin and adrenodoxin reductase.

These two types of redox partners have been functionally demonstrated in insects, and operate as shown below: