secalciferol 1-monooxygenase activity

Definition

Target type: molecularfunction

Catalysis of the reaction:2 H+ + O2 + 2 reduced [adrenodoxin] + secalciferol = calcitetrol + H2O + 2 oxidized [adrenodoxin]. [PMID:10518789, RHEA:49064]

Secalcifero 1-monooxygenase activity is the enzymatic process that catalyzes the conversion of secocalciferol (vitamin D3) into 25-hydroxyvitamin D3, also known as calcifediol. This reaction is the first step in the activation of vitamin D, which is a crucial hormone for calcium homeostasis.

The enzyme responsible for this activity, known as 25-hydroxylase, is a cytochrome P450 enzyme found primarily in the liver. It utilizes molecular oxygen (O2) and NADPH (nicotinamide adenine dinucleotide phosphate) as cofactors. The reaction involves the hydroxylation of secocalciferol at the C-25 position, introducing a hydroxyl group (OH) and forming 25-hydroxyvitamin D3.

This enzymatic activity is essential for maintaining adequate levels of vitamin D in the body. 25-hydroxyvitamin D3 is the major circulating form of vitamin D, and its production is tightly regulated to ensure sufficient levels for bone health, calcium absorption, and immune function. Deficiency in 25-hydroxylase activity can lead to vitamin D deficiency, which can manifest as rickets in children and osteomalacia in adults.'
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Proteins (1)

Compounds (2)