CYP2R1


Vitamin D 25-hydroxylase also known as cytochrome P450 2R1 is an enzyme that in humans is encoded by the CYP2R1 gene.

Function

Vitamin D 25-hydroxylase is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. Found in the liver, this enzyme is a microsomal vitamin D hydroxylase that converts vitamin D into 25-hydroxyvitamin D, which is the major circulatory form of the vitamin.

Clinical significance

An inherited mutation in the CYP2R1 gene which results in the substitution of a proline for a leucine residue at codon 99 eliminates the enzyme activity and is associated with low circulating levels of 25-hydroxyvitamin D and classic symptoms of vitamin D deficiency. The gene product which it encodes, vitamin D 25-hydroxylase, has therefore been proposed as the key enzyme in the conversion of cholecalciferol to calcidiol. Calcidiol is subsequently converted by the action of 25-hydroxyvitamin D3 1-alpha-hydroxylase to calcitriol, the active form of vitamin D3 that binds to the vitamin D receptor which mediates most of the physiological actions of the vitamin.

Interactive pathway map

Model organisms

s have been used in the study of CYP2R1 function. A conditional knockout mouse line called Cyp2r1tm1bWtsi was generated at the Wellcome Trust Sanger Institute. Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Additional screens performed: - In-depth immunological phenotyping