Reaction: CYP8B1 12-hydroxylates 4CHOL7a,27DONE
- in pathway: Sterols are 12-hydroxylated by CYP8B1
Sterol 12alpha hydroxylase (CYP8B1), associated with the endoplasmic reticulum membrane, catalyses the 12-alpha-hydroxylation of 4-Cholesten-7alpha,27-diol-3-one (4CHOL7a,27DONE) to 4-Cholesten-7alpha,12alpha,27-triol-3-one. While the human gene has been cloned (Gafvels et al. 1999), its protein product has not been characterised, and the enzymatic properties of human CYP8B1 protein are inferred from those of its well-characterised rabbit homolog (Ishida et al. 1992).
Reaction - small molecule participants:
H2O [cytosol]
NADP+ [cytosol]
4CHOL7a,12a,27TONE [endoplasmic reticulum membrane]
H+ [cytosol]
4CHOL7a,27DONE [endoplasmic reticulum membrane]
O2 [cytosol]
NADPH [cytosol]
H2O [cytosol]
NADP+ [cytosol]
4CHOL7a,12a,27TONE [endoplasmic reticulum membrane]
H+ [cytosol]
4CHOL7a,27DONE [endoplasmic reticulum membrane]
O2 [cytosol]
NADPH [cytosol]
Reactome.org reaction link: R-HSA-193845
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Reaction input - small molecules:
hydron
7alpha,26-dihydroxycholest-4-en-3-one
dioxygen
NADPH(4-)
hydron
7alpha,26-dihydroxycholest-4-en-3-one
dioxygen
NADPH(4-)
Reaction output - small molecules:
water
NADP(3-)
7alpha,12alpha,26-trihydroxycholest-4-en-3-one
water
NADP(3-)
7alpha,12alpha,26-trihydroxycholest-4-en-3-one
Reactome.org link: R-HSA-193845