CYP2R1

CYP2R1 is cytochrome P450 2R1, an enzyme which is the principal vitamin D 25-hydroxylase.^[5][6] In humans it is encoded by the CYP2R1 gene located on chromosome 11p15.2.^[7] It is expressed in the endoplasmic reticulum in liver, where it performs the first step in the activation of vitamin D by catalyzing the formation of 25-hydroxyvitamin D.^[8]

Vitamin D 25-hydroxylase activity is also possessed by some other cytochrome P450 enzymes, in particular CYP27A1, which is found in mitochondria.^[8][9]

Function

CYP2R1 is a member of the cytochrome P450 superfamily of enzymes.^[10] The cytochrome P450 proteins are mono-oxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.^[10]

CYP2R1 is present in the

The conversion of vitamin D, especially cholecalciferol, to 25(OH)D (calcifediol) is one of the key steps in the vitamin D hormonal system. The CYP2R1 enzymatic activity achieving this process was previously thought to be constitutively expressed and stable, so that serum 25(OH)D was a measure of the supply of vitamin D.[9]

CYP2R1 is now known to be regulated, with variations in the expression and activity of CYP2R1 affecting circulating 25(OH)D.

Click on genes, proteins and metabolites below to link to respective articles. [§ 1]

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|alt=Vitamin D Synthesis Pathway (view / edit)]]

Vitamin D Synthesis Pathway (view / edit)

1. ^ The interactive pathway map can be edited at WikiPathways: "VitaminDSynthesis_WP1531".

Studies in mice