Adrenodoxin, putidaredoxin and terpredoxin are soluble 2Fe-2S iron-sulphurproteins that act as single electron carriers. They are a subgroup of the ferredoxinfamily of iron-sulphur proteins.<p>In mitochondrial monooxygenase systems, adrenodoxin transfers an electron fromNADPH:adrenodoxin reductase to membrane-bound P450 [<cite idref="PUB00003474"/>]. In bacteria, putidaredoxinand terpredoxin serve as electron carriers between corresponding NADH-dependent ferredoxinreductases and soluble P450 [<cite idref="PUB00002613"/>, <cite idref="PUB00002723"/>]. The exact functions of other membersof this family are not known.</p>