25-Hydroxyvitamin D3

Last modified: Thu Jun 3 18:22:49 BST 2004

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

Trivial names: 25-Hydroxyvitamin D3; 25-Hydroxycholecalciferol; Calcidiol
Systematic name: (5Z,7E)-(3S)-9,10-Secocholesta-5,7,10(19)-triene-3,25-diol
Molecular formula: C27H44O2

Substrate [1]

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.-.-

Substrate [2]

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

Product [3]

Pathway: Vitamin D3 -> 25-Hydroxyvitamin D3
Reaction: sterol hydroxylation at C25
Enzyme: P450cc25 (vitamin D3 25-hydroxylase), CYP27
EC 1.14.-.-


  1. 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.
  2. 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.
  3. Usui, E., Noshiro, M., Ohyama, Y. and Okuda, K. (1990) Unique property of liver mitochondrial P450 to catalyze the two physiologically important reactions involved in both cholesterol catabolism and vitamin D activation. FEBS Lett. 274, 175-177.

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