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Proteins/UNIPROT:O15528
A cytochrome P450 monooxygenase involved in vitamin D metabolism and in calcium and phosphorus homeostasis. Catalyzes the rate-limiting step in the activation of vitamin D in the kidney, namely the hydroxylation of 25-hydroxyvitamin D3/calcidiol at the C1alpha-position to form the hormonally active form of vitamin D3, 1alpha,25-dihydroxyvitamin D3/calcitriol that acts via the vitamin D receptor (VDR). Has 1alpha-hydroxylase activity on vitamin D intermediates of the CYP24A1-mediated inactivation pathway. Converts 24R,25-dihydroxyvitamin D3/secalciferol to 1-alpha,24,25-trihydroxyvitamin D3, an active ligand of VDR. Also active on 25-hydroxyvitamin D2. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via FDXR/adrenodoxin reductase and FDX1/adrenodoxin..
Function from UniProtKB (O15528), read 2026-09-23. CC BY 4.0.
Curated compounds routed: 0
2 rows
59 statements
59 statements · 7 reference databases · Subject: CYP27B1 · Sources: gene ontology, Hetionet, Human-GEM, Reactome, Rhea, UniProt, WikiPathways
7 reactions
calcidiol+proton+NADPH(4-)+dioxygencalcitriol+water+NADP(3-)
Catalysed by CYP27B1 & CUBN & GC & LRP2
Reaction pageLeft to rightBalancedEC 1.14.15.18cytosol
Human-GEM MAR02118CC BY 4.0Reference data
10 names
Resolves to: CYP27B1
Reaction pageLeft to rightBalancedEC 1.14.15.18mitochondrial matrix
Human-GEM MAR08004CC BY 4.0Reference data
calcidiol+proton+NADPH(4-)+dioxygencalcitriol+water+NADP(3-)
Catalysed by CYP27B1 & CUBN & GC & LRP2
Reaction pageLeft to rightBalancedEC 1.14.15.18mitochondrial matrix
Human-GEM MAR08008CC BY 4.0Reference data
calcidiol+2reduced [adrenodoxin]+dioxygen+2hydroncalcitriol+2oxidized [adrenodoxin]+water
Catalysed by CYP27B1
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:20573CC BY 4.0Reference data
CHEBI:86319+2reduced [adrenodoxin]+dioxygen+2hydronCHEBI:86320+2oxidized [adrenodoxin]+water
Catalysed by CYP27B1
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:49048CC BY 4.0Reference data
secalciferol+2reduced [adrenodoxin]+dioxygen+2hydroncalcitetrol+2oxidized [adrenodoxin]+water
Catalysed by CYP27B1
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:49064CC BY 4.0Reference data
25-hydroxy-24-oxocalciol+2reduced [adrenodoxin]+dioxygen+2hydron(1S)-1,25-dihydroxy-24-oxocalciol+2oxidized [adrenodoxin]+water
Catalysed by CYP27B1
Reaction pageLeft to rightBalance undeterminable
Rhea RHEA:49068CC BY 4.0Reference data