steroid 11β-monooxygenase

ster·oid 11β-mono·oxy·gen·ase (sterґoid mon″o-okґsə-jən-ās) [EC 1.14.15.4] an enzyme of the oxidoreductase class that catalyzes the NADPH-dependent hydroxylation of steroids at the 11 position as a step in the synthesis of steroid hormones. The enzyme is a mitochondrial cytochrome P-450 acting as a terminal oxidase in an electron transport chain that also includes adrenodoxin and a flavoprotein. Deficiency of the enzyme, an autosomal recessive trait, is called 11β-hydroxylase deficiency and causes congenital adrenal hyperplasia (type IV). The enzyme may include the enzyme activities of corticosterone 18-monooxygenase (q.v.). Called also 11β-hydroxylase.