|Superclasses:||a vitamin → a vitamin D|
Vitamin D refers to a group of fat-soluble secosteroids responsible for enhancing intestinal absorption of calcium, iron, magnesium, phosphate and zinc.
In humans, the most important compounds in this group are vitamin D3 (cholecalciferol), which is produced in animal skin from 7-dehydrocholesterol after exposure to UV light and heat, and vitamin D2 (ergocalciferol), which is produced in plants and fungi from ergosterol after exposure to UV light.
In its activated form, vitamin D3 is necessary for optimal absorption and regulation of dietary Ca2+ and phosphate. This nutrient is essential for the prevention of rickets, a bone-softening disease (reviewed in [DeLuca04, Dusso05, Lips06]).
There is controversy in the literature as to whether supplemental vitamin D2 is as effective as vitamin D3 in maintaining circulating levels of the calcidiol vitamin D metabolite [Houghton06, Holick08]. The production of vitamin D analogs is n active area of research (reviewed in [Prosser04].
Chemical Formula: C28H44O
Molecular Weight: 396.66 Daltons
Monoisotopic Molecular Weight: 396.3392160345 Daltons
Standard Gibbs Free Energy of Change Formation (ΔfG'° in kcal/mol): 489.6793 [Latendresse13]
Reactions known to produce the compound:
Not in pathways:
ergosterol + UV light → vitamin D2
Enzymes inhibited by vitamin D2, sorted by the type of inhibition, are:Inhibitor (Mechanism unknown) of: calcitriol 24-hydroxylase [Ohyama91]
This compound has been characterized as an alternative substrate of the following enzymes: vitamin D 25-hydroxylase
Holick08: Holick MF, Biancuzzo RM, Chen TC, Klein EK, Young A, Bibuld D, Reitz R, Salameh W, Ameri A, Tannenbaum AD (2008). "Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D." J Clin Endocrinol Metab 93(3);677-81. PMID: 18089691
Ohyama91: Ohyama Y, Okuda K (1991). "Isolation and characterization of a cytochrome P-450 from rat kidney mitochondria that catalyzes the 24-hydroxylation of 25-hydroxyvitamin D3." J Biol Chem 266(14);8690-5. PMID: 2026586
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