Vitamin D3 24-hydroxylase explained

Vitamin D3 24-hydroxylase
Ec Number:	1.14.15.16

Vitamin D3 24-hydroxylase (CYP24A1) is an enzyme with systematic name calcitriol,NADPH:oxygen oxidoreductase (24-hydroxylating).^{[1] [2] [3] [4] [5] [6] [7]} This enzyme catalyses the following chemical reaction

(1) calcitriol + NADPH + H⁺ + O₂

\rightleftharpoons calcitetrol + NADP⁺ + H₂O

(2) calcidiol + NADPH + H⁺ + O₂

\rightleftharpoons secalciferol + NADP⁺ + H₂O

Vitamin D3 24-hydroxylase is a heme-thiolate enzyme (P-450).

Notes and References

1. Masuda S, Strugnell SA, Knutson JC, St-Arnaud R, Jones G . Evidence for the activation of 1alpha-hydroxyvitamin D2 by 25-hydroxyvitamin D-24-hydroxylase: delineation of pathways involving 1alpha,24-dihydroxyvitamin D2 and 1alpha,25-dihydroxyvitamin D2 . Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids . 1761 . 2 . 221–34 . February 2006 . 16516540 . 10.1016/j.bbalip.2006.01.004 .
2. Hamamoto H, Kusudo T, Urushino N, Masuno H, Yamamoto K, Yamada S, Kamakura M, Ohta M, Inouye K, Sakaki T . Structure-function analysis of vitamin D 24-hydroxylase (CYP24A1) by site-directed mutagenesis: amino acid residues responsible for species-based difference of CYP24A1 between humans and rats . Molecular Pharmacology . 70 . 1 . 120–8 . July 2006 . 16617161 . 10.1124/mol.106.023275 . 7458859 .
3. Sakaki T, Kagawa N, Yamamoto K, Inouye K . Metabolism of vitamin D3 by cytochromes P450 . Frontiers in Bioscience . 10 . 119–34 . January 2005 . 15574355 . 10.2741/1514 . free .
4. Prosser DE, Kaufmann M, O'Leary B, Byford V, Jones G . Single A326G mutation converts human CYP24A1 from 25-OH-D3-24-hydroxylase into -23-hydroxylase, generating 1alpha,25-(OH)2D3-26,23-lactone . Proceedings of the National Academy of Sciences of the United States of America . 104 . 31 . 12673–8 . July 2007 . 17646648 . 1937525 . 10.1073/pnas.0702093104 . 2007PNAS..10412673P . free .
5. Kusudo T, Sakaki T, Abe D, Fujishima T, Kittaka A, Takayama H, Hatakeyama S, Ohta M, Inouye K . Metabolism of A-ring diastereomers of 1alpha,25-dihydroxyvitamin D3 by CYP24A1 . Biochemical and Biophysical Research Communications . 321 . 4 . 774–82 . September 2004 . 15358094 . 10.1016/j.bbrc.2004.07.040 .
6. Sawada N, Kusudo T, Sakaki T, Hatakeyama S, Hanada M, Abe D, Kamao M, Okano T, Ohta M, Inouye K . Novel metabolism of 1 alpha,25-dihydroxyvitamin D3 with C24-C25 bond cleavage catalyzed by human CYP24A1 . Biochemistry . 43 . 15 . 4530–7 . April 2004 . 15078099 . 10.1021/bi030207f .
7. Prosser DE, Jones G . Enzymes involved in the activation and inactivation of vitamin D . Trends in Biochemical Sciences . 29 . 12 . 664–73 . December 2004 . 15544953 . 10.1016/j.tibs.2004.10.005 .