Vitamin D metabolic enzymes

Vitamin D metabolic enzymes are a group of cytochrome P450 enzymes, primarily CYP2R1, CYP27B1, and CYP24A1, that regulate the activation and inactivation of vitamin D. CYP2R1 performs the initial 25-hydroxylation in the liver, while CYP27B1 catalyzes the production of the active hormone, 1,25-dihydroxyvitamin D (calcitriol), in the kidneys and other tissues. CYP24A1 serves as the primary catabolic enzyme, degrading active metabolites to maintain physiological balance and prevent toxicity. These enzymes are essential for calcium and phosphate homeostasis, bone mineralization, and the modulation of immune and cell-proliferative pathways. Dysregulation of these enzymes is associated with rickets, osteomalacia, chronic kidney disease, and certain cancers. Pharmacological intervention includes the use of vitamin D analogs to bypass metabolic steps or CYP24A1 inhibitors to prolong the half-life of active vitamin D in therapeutic settings.

Other names

Vitamin D hydroxylasesVitamin D activating and inactivating enzymesCYP2R1CYP27B1CYP24A1Vitamin D 25-hydroxylase25-hydroxyvitamin D 1-alpha-hydroxylase1,25-dihydroxyvitamin D 24-hydroxylase

Drugs targeting these enzymes primarily function as exogenous substrates for activation (e.g., cholecalciferol), synthetic analogs of the active metabolite (e.g., paricalcitol) that bypass specific metabolic steps, or inhibitors of catabolic enzymes (e.g., CYP24A1 inhibitors) to prolong the half-life of endogenous or therapeutic calcitriol.