EC 1.14.99.9 (steroid 17alpha-monooxygenase) inhibitor An EC 1.14.99.* (miscellaneous oxidoreductase acting on paired donors, with incorporation or reduction of molecular oxygen) inhibitor that interferes with the action of cytochrome P450 17-α-hydroxylase/C17,20-lyase (EC 1.14.99.9). CHEBI:68640 EC 1.14.99.* (miscellaneous oxidoreductase acting on paired donors, with incorporation or reduction of molecular oxygen) inhibitor