CYP17A1 cleaves 17aHPREG to DHA

Stable Identifier
R-HSA-193070
Type
Reaction [transition]
Species
Homo sapiens
Compartment
Synonyms
Side chain cleavage of 17alpha-hydroxypregnenolone to yield DHA, 17alpha-hydroxyprenenolone + NADPH + H+ + O2 => DHA (dehydroepiandrostenedione) + NADP+ + H2O + acetaldehyde
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17-alpha-hydroxypregnenolone, NADPH + H+, and O2 react to form DHA (dehydroepiandrostenedione), NADP+, H2O, and acetaldehyde. CYP17 (which also catalyzes 17-alpha-hydroxylation) catalyzes this lyase reaction. There are marked species differences in which substrate is used for this lyase activity. The human enzyme prefers 17alpha-pregnenolone (delta5 steroid) as substrate (Brock, BJ, Waterman, MR, 1999). Corticotropin (Adrenocorticotropic hormone, ACTH) acts through the ACTH receptor called melanocortin receptor type 2 (MC2R) to stimulate steroidogenesis, increasing the production of androgens (McKenna et al, 1997).

Literature References
PubMed ID Title Journal Year
10406467 Molecular modeling of human P450c17 (17alpha-hydroxylase/17,20-lyase): insights into reaction mechanisms and effects of mutations

Auchus, RJ, Miller, WL

Mol Endocrinol 1999
9536209 A critical review of the origin and control of adrenal androgens

McKenna, TJ, Fearon, U, Clarke, D, Cunningham, SK

Baillieres Clin Obstet Gynaecol 1997
Participants
Participates
Catalyst Activity

steroid 17-alpha-monooxygenase activity of CYP17A1 [endoplasmic reticulum membrane]

This event is regulated
Positively by
Regulator
Summation

Corticotropin (Adrenocorticotropic hormone, ACTH) acts through the ACTH receptor called melanocortin receptor type 2 (MC2R) to stimulate steroidogenesis, increasing the production of androgens (McKenna et al, 1997).

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