1alpha,25-Dihydroxyvitamin D3

Last modified: Thu Jun 3 18:24:20 BST 2004

Vitamin D3 carbon nomenclature
Summary of P450-dependent vitamin D3 metabolism

Trivial names: 1alpha,25-Dihydroxyvitamin D3; 1alpha,25-Dihydroxycholecalciferol; Calcitriol
Systematic name: (5Z,7E)-(1S,3R)-9,10-Secocholesta-5,7,10(19)-triene-1,3,25-triol
Molecular formula: C27H44O3
CAS Number: 32222-06-3
Merck Index (11th Ed) Number: 1641

Substrate [1]

Pathway: 1alpha,25-Dihydroxyvitamin D3 -> 1alpha,24,25-Trihydroxyvitamin D3
Reaction: sterol hydroxylation at C24
Enzyme: P450cc24 (25-hydroxyvitamin D3 24-hydroxylase), CYP24
EC 1.14.-.-

Product [2]

Pathway: 25-Hydroxyvitamin D3 -> 1alpha,25-Dihydroxyvitamin D3
Reaction: steroid alpha-hydroxylation at C1
Enzyme: P4501alpha (25-hydroxyvitamin D3 1alpha-hydroxylase), CYP27
EC 1.14.-.-


  1. Dilworth, F.J., Scott, I., Green, A., Strugnell, S., Guo, Y.-D., Roberts, E.A., Kremer, R., Calverley, M.J., Makin, H.L.J. and Jones, G. (1995) Different mechanisms of hydroxylation site selection by liver and kidney cytochrome P450 species (CYP27 and CYP24) involved in vitamin D metabolism. J. Biol. Chem. 270, 16766-16774.
  2. Axén, E., Postlind, H., Sjöberg, H. and Wikvall, K. (1994) Liver mitochondrial cytochrome P450 CYP27 and recombinant-expressed human CYP27 catalyze 1alpha-hydroxylation of 25-hydroxyvitamin D3. Proc. Natl. Acad. Sci. USA 91, 10014-10018.

Back to the Directory of P450-containing Systems home page: