EC: 4.1.2.30
Pathways: 17 a -Hydroxypregnenolone --> Dehydroepiandrosterone
17 a -Hydroxyprogesterone --> Androstenedione

Reaction: cleavage of steroid C17-C20 bond
Cofactors:
Inhibitors: Ketoconazole
Enzyme Synonyms: P450c17 (steroid 17 a - hydroxylase/17,20-lyase/17,20 desmolase); CYP17