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EC 1.14.99.9 Details
show Brenda entryEC number
1.14.99.9
Accepted name
steroid 17α-monooxygenase
Reaction
a C21-steroid + [reduced NADPH—hemoprotein reductase] + O2 = a 17α-hydroxy-C21-steroid + [oxidized NADPH—hemoprotein reductase] + H2O;;
Other name(s)
steroid 17α-hydroxylase,
cytochrome P-45017α,
cytochrome P-450 (P-45017α,lyase),
17α-hydroxylase-C17,20 lyase,
CYP17,
CYP17A1 (gene name)
Systematic name
steroid,NADPH—hemoprotein reductase:oxygen oxidoreductase (17α-hydroxylating)
CAS registry number
9029-67-8
Comment
Requires NADPH and EC 1.6.2.4, NADPH—hemoprotein reductase. A microsomal hemeprotein that catalyses two independent reactions at the same active site - the 17α-hydroxylation of pregnenolone and progesterone, which is part of glucocorticoid hormones biosynthesis, and the conversion of the 17α-hydroxylated products via a 17,20-lyase reaction to form androstenedione and dehydroepiandrosterone, leading to sex hormone biosynthesis (EC 4.1.2.30, 7α-hydroxyprogesterone aldolase). The ratio of the 17α-hydroxylase and 17,20-lyase activities is an important factor in determining the directions of steroid hormone biosynthesis towards biosynthesis of glucocorticoid or sex hormones.
History
created 1961 as EC 1.99.1.9, transferred 1965 to EC 1.14.1.7, transferred 1972 to EC 1.14.99.9, modified 2013, deleted 2015
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1 Oxidoreductases
1.1 Acting on the CH-OH group of donors
1.14.99.5 created 1972, modified 1986, modified 2000, deleted 2000 1.14.99.6 created 1972, modified 2000, deleted 2000 1.14.99.8 created 1972, deleted 1984 1.14.99.13 created 1972, deleted 1984 1.14.99.16 created 1972, deleted 2002 1.14.99.17 created 1972, deleted 1976 1.14.99.18 created 1976, modified 1999, deleted 2003 1.14.99.25 created 1986, deleted 2000
