Associates in vitro with the adrenodoxin-like protein MFDX1 to form an efficient low potential electron transfer chain that is able to reduce cytochrome C (PubMed:12714594, PubMed:13677469). Functions as accessory mitochondrial protein involved with BIO2 in the plant biotin synthase reaction (PubMed:12714594). H(+) + NADP(+) + 2 reduced [adrenodoxin] = NADPH + 2 oxidized [adrenodoxin] Belongs to the ferredoxin--NADP reductase type 1 family.