Reaction: Pregnenolone is dehydrogenated to form pregn-5-ene-3,20-dione
- in pathway: Mineralocorticoid biosynthesis
Pregnenolone and NAD+ react to form pregn-5-ene-3,20-dione and NADH + H+. This reaction is catalyzed by the 3 beta-hydroxysteroid activity of 3-beta-hydroxysteroid dehydrogenase/isomerase (HSD3B) enzyme associated with the endoplasmic reticulum membrane. The active form of the enzyme is a homodimer. The enzyme occurs in two isoforms that are similar in their biochemical properties but differ in their tissue expression: type I (HSD3B1) is found in placenta and skin, while type II (HSD3B2) is found in the adrenal glands and gonads.
Reaction - small molecule participants:
H+ [cytosol]
pregn-5-ene-3,20-dione [cytosol]
NADH [cytosol]
PREG [cytosol]
NAD+ [cytosol]
Reactome.org reaction link: R-HSA-196350
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Reaction input - small molecules:
pregnenolone
NAD(1-)
Reaction output - small molecules:
hydron
pregn-5-ene-3,20-dione
NADH(2-)
Reactome.org link: R-HSA-196350