Essential for the synthesis of various steroid hormones. Participates in the reduction of mitochondrial cytochrome P450 for steroidogenesis. Transfers electrons from adrenodoxin reductase to CYP11A1, a cytochrome P450 that catalyzes cholesterol side-chain cleavage. Does not form a ternary complex with adrenodoxin reductase and CYP11A1 but shuttles between the two enzymes to transfer electrons. Binds 1 [2Fe-2S] cluster. Belongs to the adrenodoxin/putidaredoxin family.