Reaction: CYP11A1 cleaves 20a,22b-DHCHOL
- in pathway: Pregnenolone biosynthesis
20alpha,22beta-hydroxycholesterol (20a,22b-DHCHOL), NADPH + H+, and O2 react to form pregnenolone (PREG), isocaproaldehyde (ISCAL), NADP+ and H2O. This cleavage reaction is catalysed by CYP11A (P450scc) associated with the inner mitochondrial membrane (Strushkevich et al. 2011). PREG is substantially more hydrophilic than cholesterol (CHOL) and hydroxycholesterol (HCHOL) and is released into the mitochondrial matrix.
Reaction - small molecule participants:
PREG [mitochondrial matrix]
NADP+ [mitochondrial matrix]
ISCAL [mitochondrial matrix]
H2O [mitochondrial matrix]
O2 [mitochondrial matrix]
20a,22b-DHCHOL [mitochondrial inner membrane]
H+ [mitochondrial matrix]
NADPH [mitochondrial matrix]
PREG [mitochondrial matrix]
NADP+ [mitochondrial matrix]
ISCAL [mitochondrial matrix]
H2O [mitochondrial matrix]
O2 [mitochondrial matrix]
20a,22b-DHCHOL [mitochondrial inner membrane]
H+ [mitochondrial matrix]
NADPH [mitochondrial matrix]
Reactome.org reaction link: R-HSA-193101
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Reaction input - small molecules:
dioxygen
(20R,22R)-20,22-dihydroxycholesterol
hydron
NADPH
dioxygen
(20R,22R)-20,22-dihydroxycholesterol
hydron
NADPH
Reaction output - small molecules:
pregnenolone
NADP(+)
4-methylpentanal
water
pregnenolone
NADP(+)
4-methylpentanal
water
Reactome.org link: R-HSA-193101