Side chain cleavage of 17alpha-hydroxypregnenolone to yield DHA

Stable Identifier
R-HSA-193070
Type
Reaction
Species
Homo sapiens
Compartment
Synonyms
17alpha-hydroxyprenenolone + NADPH + H+ + O2 => DHA (dehydroepiandrostenedione) + NADP+ + H2O + acetaldehyde
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Summation

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).

Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
steroid 17-alpha-monooxygenase activity of CYP17A1 [endoplasmic reticulum membrane]
Physical Entity
Activity
This entity is regulated by
Orthologous Events
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