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Information on EC 1.14.14.19 - steroid 17alpha-monooxygenase and Organism(s) Ovis aries and UniProt Accession Q29497

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IUBMB Comments
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 17alpha-hydroxylation of pregnenolone and progesterone, which is part of glucocorticoid hormones biosynthesis, and the conversion of the 17alpha-hydroxylated products via a 17,20-lyase reaction to form androstenedione and dehydroepiandrosterone, leading to sex hormone biosynthesis (EC 1.14.14.32, 17alpha-hydroxyprogesterone deacetylase). The ratio of the 17alpha-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.
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Ovis aries
UNIPROT: Q29497
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Word Map
The taxonomic range for the selected organisms is: Ovis aries
The enzyme appears in selected viruses and cellular organisms
Synonyms
17,20-lyase, 17ohd, p450 17, cyp 17, p450(17alpha), cytochrome p450c17alpha, cytochrome p450 17alpha-hydroxylase, 17-hydroxylase/17,20-lyase, 17 alpha-hydroxylase/c17,20-lyase, 17alpha-ohase, more
SYNONYM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
cytochrome P450 17alpha-hydroxylase/17,20-lyase
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17alpha-hydroxylase-C17,20 lyase
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CYPXVII
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cytochrome P-450 (P45017alpha,lyase)
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cytochrome P45017alpha
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P450-C17
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Steroid 17-alpha-hydroxylase/17,20 lyase
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steroid 17alpha-hydroxylase
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
redox reaction
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oxidation
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reduction
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hydroxylation
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PATHWAY SOURCE
PATHWAYS
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-, -, -, -
SYSTEMATIC NAME
IUBMB Comments
steroid,NADPH-hemoprotein reductase:oxygen oxidoreductase (17alpha-hydroxylating)
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 17alpha-hydroxylation of pregnenolone and progesterone, which is part of glucocorticoid hormones biosynthesis, and the conversion of the 17alpha-hydroxylated products via a 17,20-lyase reaction to form androstenedione and dehydroepiandrosterone, leading to sex hormone biosynthesis (EC 1.14.14.32, 17alpha-hydroxyprogesterone deacetylase). The ratio of the 17alpha-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.
CAS REGISTRY NUMBER
COMMENTARY hide
9029-67-8
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SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
pregnenolone + [reduced NADPH-hemoprotein reductase] + O2
17alpha-hydroxypregnenolone + [oxidized NADPH-hemoprotein reductase] + H2O
show the reaction diagram
-
-
-
?
progesterone + [reduced NADPH-hemoprotein reductase] + O2
17alpha-hydroxyprogesterone + [oxidized NADPH-hemoprotein reductase] + H2O
show the reaction diagram
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-
-
?
additional information
?
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the bifunctional enzyme catalyzes two types of reactions, namely, a 17alpha-hydroxylation reaction and a 17,20-lyase reaction
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-
?
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
pregnenolone + [reduced NADPH-hemoprotein reductase] + O2
17alpha-hydroxypregnenolone + [oxidized NADPH-hemoprotein reductase] + H2O
show the reaction diagram
-
-
-
?
progesterone + [reduced NADPH-hemoprotein reductase] + O2
17alpha-hydroxyprogesterone + [oxidized NADPH-hemoprotein reductase] + H2O
show the reaction diagram
-
-
-
?
additional information
?
-
the bifunctional enzyme catalyzes two types of reactions, namely, a 17alpha-hydroxylation reaction and a 17,20-lyase reaction
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-
?
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
0.0017 - 0.0019
pregnenolone
0.0016 - 0.0018
progesterone
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.4
assay at
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GenBank accession numbers L40335 and AF251388 encodíng isozymes 1 and 2; two isozymes of cytochrome P450 17alpha-hydroxylase/17,20-lyase, that differ in two nucleotides, resulting in variants Ser210Gly and Tyr464Asn
UniProt
Manually annotated by BRENDA team
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
evolution
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the CYP17 enzymes from various species have 46-98% sequence homology, depending on the evolutionary distance between the organisms. Enzymes from different mammalian species show relatively high homology of amino acid sequences, but have different types of activity and different requirements for cytochrome b5
metabolism
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CYP17-dependent alternative steroids biosynthesis, overview
physiological function
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CYP17A1 catalyzes the 17alpha-hydroxylase and 17,20-lyase reactions using various C21-steroids as substrates, overview
additional information
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the following factors contribute to the regulation of CYP17 activities: 1. the ratio of NADPH-cytochrome P450 reductase to CYP17, i.e. the rate of delivery of reducing equivalents to the P450, 2. the presence of cytochrome b5 either as an allosteric effector or as an electron donor, 3. phosphorylation of the CYP17 protein, which affects its stability and activity, and 4. retention of the intermediate, 17-OHP5 or 17-OHP4, in the active site of CYP17, which facilitates the 17,20-lyase reaction. Expression level of CYP17A1 in adrenals is regulated by ACTH and by gonadotropic hormone in the testis and ovaries
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION?
CP17A_SHEEP
509
0
57308
Swiss-Prot
Secretory Pathway (Reliability: 2)
CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
DNA and amino acid sequence determination and analysis, CYP17 genotyping, realtime PCR expression analysis
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Hough, D.; Cloete, S.W.; Storbeck, K.; Swart, A.C.; Swart, P.
Cortisol production in sheep is influenced by the functional expression of two cytochrome P450 17alpha-hydroxylase/17,20-lyase (CYP17) isoforms
J. Anim. Sci.
91
1193-1206
2013
Ovis aries (Q29497)
Manually annotated by BRENDA team