17α-hydroxyprogesterone aldolase

17α-hy·droxy·pro·ges·ter·one al·do·lase (hi-drok″se-pro-jesґtə-rōn alґdo-lās) [EC 4.1.2.30] an enzyme of the lyase class that catalyzes the cleavage of the bond between carbons 17 and 20 in 17α-hydroxyprogesterone to form Δ⁴-androstenedione, an androgen. It also catalyzes the conversion of 17α-hydroxypregnenolone to dehydroepiandrosterone. The enzyme activity is part of the enzyme steroid 17α-monooxygenase. Deficiency of enzyme activity is called 17,20-lyase deficiency. Called also 17,20-lyase and 17,20-desmolase.