Vitamin D activating enzymes (CYP2R1, CYP27A1, CYP3A4, CYP2J2, CYP27B1)

Vitamin D activating enzymes are a group of cytochrome P450 monooxygenases responsible for the stepwise metabolic activation of vitamin D into its active form. Key members include 25-hydroxylases (CYP2R1, CYP27A1, CYP3A4, CYP2J2), which convert vitamin D to 25-hydroxyvitamin D (calcidiol) predominantly in the liver, and 1α-hydroxylase (CYP27B1), which converts calcidiol to the biologically active 1,25-dihydroxyvitamin D (calcitriol) in the kidney. These enzymes regulate serum levels of vitamin D metabolites that control calcium and phosphate balance, bone mineralization, immune function, and cell proliferation. Mutations or altered activity are associated with rickets, osteomalacia, and other disorders of calcium metabolism. They are considered therapeutic targets for modulating vitamin D status, with activity measurable via serum metabolites and potential modulation by vitamin D analog drugs.

Other names

Vitamin D hydroxylase25-hydroxylase1α-hydroxylaseCYP27A1CYP2R1CYP3A4CYP2J2CYP27B1

Catalyze hydroxylation of vitamin D precursors to produce active hormone (calcitriol) for interaction with vitamin D receptor (VDR) Regulate balance of active/inactive vitamin D by further hydroxylation and inactivation