Essential for the synthesis of various steroid hormones (PubMed:20547883, PubMed:21636783). Participates in the reduction of mitochondrial cytochrome P450 for steroidogenesis (PubMed:20547883, PubMed:21636783). Transfers electrons from adrenodoxin reductase to CYP11A1, a cytochrome P450 that catalyzes cholesterol side-chain cleavage (PubMed:20547883, PubMed:21636783). Does not form a ternary complex with adrenodoxin reductase and CYP11A1 but shuttles between the two enzymes to transfer electrons (By similarity).