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HMDB Protein ID HMDBP12698
Secondary Accession Numbers None
Name 1,25-dihydroxyvitamin D(3) 24-hydroxylase, mitochondrial
  1. 24-OHase
  2. Vitamin D(3) 24-hydroxylase
  3. Cytochrome P450 24A1
  4. Cytochrome P450-CC24
Gene Name CYP24A1
Protein Type Unknown
Biological Properties
General Function Not Available
Specific Function A cytochrome P450 monooxygenase with a key role in vitamin D catabolism and calcium homeostasis. Via C24-oxidation pathway, catalyzes the inactivation of both the vitamin D precursor calcidiol (25-hydroxyvitamin D(3)) and the active hormone calcitriol (1-alpha,25-dihydroxyvitamin D(3)). With initial hydroxylation at C-24 (via C24-oxidation pathway), performs a sequential 6-step oxidation of calcitriol leading to the formation of the biliary metabolite calcitroic acid. Hydroxylates at C-24 or C-25 other vitamin D active metabolites, such as CYP11A1-derived secosteroids 20S-hydroxycholecalciferol and 20S,23-dihydroxycholecalciferol. 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.
  • MicroRNAs in cancer
  • Parathyroid hormone synthesis, secretion and action
  • Steroid biosynthesis
Reactions Not Available
GO Classification
Biological Process
fatty acid omega-oxidation
vitamin D metabolic process
osteoblast differentiation
vitamin D catabolic process
response to vitamin D
Cellular Component
Molecular Function
vitamin D 24-hydroxylase activity
1-alpha,25-dihydroxyvitamin D3 23-hydroxylase activity
25-hydroxycholecalciferol-23-hydroxylase activity
vitamin D 25-hydroxylase activity
iron ion binding
1-alpha,25-dihydroxyvitamin D3 24-hydroxylase activity
25-hydroxycholecalciferol-24-hydroxylase activity
heme binding
Cellular Location Not Available
Gene Properties
Chromosome Location Not Available
Locus Not Available
SNPs Not Available
Gene Sequence Not Available
Protein Properties
Number of Residues 514
Molecular Weight 59452.655
Theoretical pI 9.031
Pfam Domain Function
Signals Not Available
Transmembrane Regions Not Available
Protein Sequence Not Available
GenBank ID Protein Not Available
UniProtKB/Swiss-Prot ID Q64441
UniProtKB/Swiss-Prot Entry Name CP24A_MOUSE
PDB IDs Not Available
GenBank Gene ID Not Available
GeneCard ID Not Available
GenAtlas ID Not Available
HGNC ID Not Available
General References
  1. Tsujikawa H, Kurotaki Y, Fujimori T, Fukuda K, Nabeshima Y: Klotho, a gene related to a syndrome resembling human premature aging, functions in a negative regulatory circuit of vitamin D endocrine system. Mol Endocrinol. 2003 Dec;17(12):2393-403. Epub 2003 Oct 3. [PubMed:14528024 ]
  2. Akeno N, Saikatsu S, Kawane T, Horiuchi N: Mouse vitamin D-24-hydroxylase: molecular cloning, tissue distribution, and transcriptional regulation by 1alpha,25-dihydroxyvitamin D3. Endocrinology. 1997 Jun;138(6):2233-40. [PubMed:9165006 ]
  3. Itoh S, Yoshimura T, Iemura O, Yamada E, Tsujikawa K, Kohama Y, Mimura T: Molecular cloning of 25-hydroxyvitamin D-3 24-hydroxylase (Cyp-24) from mouse kidney: its inducibility by vitamin D-3. Biochim Biophys Acta. 1995 Oct 17;1264(1):26-8. doi: 10.1016/0167-4781(95)00147-9. [PubMed:7578252 ]