steroid 17α-monooxygenase

ster·oid 17α-mono·oxy·gen·ase (sterґoid mon″o-okґsə-jən-ās) [EC 1.14.99.9] an enzyme of the oxidoreductase class that catalyzes the hydroxylation of steroids at the 17 position. The enzyme is a microsomal cytochrome P-450 that accepts electrons from NADPH via a flavoprotein. The reactions catalyzed are steps in the synthesis of steroid hormones, including cortisol, androgens, and estrogens. Deficiency of the enzyme, an autosomal recessive trait, is called 17α-hydroxylase deficiency and causes congenital adrenal hyperplasia (type V). The enzyme also possesses 17α-hydroxyprogesterone aldolase activity. Called also 17α-hydroxylase.