To all interested in Vitamin D: CYP2R1 is a major vitamin D 25-hydroxylase

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Here is another enzye involved, thus another piece of the puzzle;

Toxicol Appl Pharmacol. 2005 Jun 27; [Epub ahead of print]

Novel extrahepatic cytochrome P450s.

Karlgren M, Miura SI, Ingelman-Sundberg M.

Division of Molecular Toxicology, Institute of Environmental

Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden.

The cytochrome P450 enzymes are highly expressed in the liver and are

involved in the metabolism of xenobiotics. Because of the initiatives

associated with the Human Genome Project, a great progress has

recently been seen in the identification and characterization of

novel extrahepatic P450s, including CYP2S1, CYP2R1, CYP2U1 and

CYP2W1.

Like the hepatic enzymes, these P450s may play a role in the tissue-

specific metabolism of foreign compounds, but they may also have

important endogenous functions.

CYP2S1 has been shown to metabolize all-trans retinoic acid and

CYP2R1 is a major vitamin D 25-hydroxylase.

Regarding their metabolism of xenobiotics, much remains to be

established, but CYP2S1 metabolizes naphthalene and it is likely that

these P450s are responsible for metabolic activation of several

different kinds of xenobiotic chemicals and contribute to

extrahepatic toxicity and carcinogenesis.

PMID: 15987645 [PubMed - as supplied by publisher]