Ketosteroid monooxygenase

Ketosteroid monooxygenase (EC 1.14.13.54, steroid-ketone monooxygenase, progesterone, NADPH2:oxygen oxidoreductase (20-hydroxylating, ester-producing), 17alpha-hydroxyprogesterone, NADPH₂:oxygen oxidoreductase (20-hydroxylating, side-chain cleaving), androstenedione, NADPH₂:oxygen oxidoreductase (17-hydroxylating, lactonizing)) is an enzyme with systematic name ketosteroid,NADPH:oxygen oxidoreductase (20-hydroxylating, ester-producing/20-hydroxylating, side-chain cleaving/17-hydroxylating, lactonizing). This enzyme catalyses the following chemical reaction

ketosteroid + NADPH + H⁺ + O₂ ⇌ steroid ester/lactone + NADP⁺ + H₂O (general reaction)(1) progesterone + NADPH + H⁺ + O₂ ⇌ testosterone acetate + NADP⁺ + H₂O(2) androstenedione + NADPH + H⁺ + O₂ ⇌ testololactone + NADP⁺ + H₂O(3) 17alpha-hydroxyprogesterone + NADPH + H⁺ + O₂ ⇌ androstenedione + acetate + NADP⁺ + H₂O

Ketosteroid monooxygenase is a single FAD-containing enzyme that catalyses three types of monooxygenase reaction.