Reaction: CYP27B1 hydroxylates 25(OH)D to 1,25(OH)2D
- in pathway: Vitamin D (calciferol) metabolism
The second step in vitamin D activation requires hydroxylation of 25-hydroxyvitamin D (calcidiol, 25(OH)D) to 1-alpha, 25-dihydroxyvitamin D (1,25(OH)2D). This conversion is mediated by 25-hydroxyvitamin D-1-alpha hydroxylase (CYP27B1), an outer mitochondrial membrane-resident protein (Zehnder et al. 2002, Fritsche et al. 2003, Sawada et al. 1999).
Reaction - small molecule participants:
H2O [cytosol]
1,25(OH)2D [cytosol]
NADP+ [cytosol]
25(OH)D [cytosol]
H+ [cytosol]
O2 [cytosol]
NADPH [cytosol]
H2O [cytosol]
1,25(OH)2D [cytosol]
NADP+ [cytosol]
25(OH)D [cytosol]
H+ [cytosol]
O2 [cytosol]
NADPH [cytosol]
Reactome.org reaction link: R-HSA-209868
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Reaction input - small molecules:
calcidiol
hydron
dioxygen
NADPH(4-)
calcidiol
hydron
dioxygen
NADPH(4-)
Reaction output - small molecules:
water
calcitriol
NADP(3-)
water
calcitriol
NADP(3-)
Reactome.org link: R-HSA-209868