Incorportion of oxygen-18 into the 25-position of cholecalciferol by hepatic cholecalciferol 25-hydroxylase.
The oxygen enzymically inserted as a hydroxy function by rat liver post-mitochondrial fraction into the 25-position of cholecalciferol to giver 25-hydroxycholecaliferol is derived exclusively from molecular O2. Therefore like the other two cholecalciferol hydroxylases, i.e. 25-hydroxycholecalciferol 1alpha-hydroxylase and 25-hydroxycholecalciferol 24-hydroxylase, the cholecalciferol 25-hydroxylase is also a mono-oxygenase ('mixed-function oxidase').
D000818:Animals; D002762:Cholecalciferol / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D006900:Hydroxylation; D008099:Liver / Q000201:enzymology*; D008297:Male; D013058:Mass Spectrometry; D010104:Oxygen Radioisotopes; D051381:Rats; D013250:Steroid Hydroxylases / Q000378:metabolism*
D006887:Hydroxycholecalciferols; D010104:Oxygen Radioisotopes; D002762:Cholecalciferol; D013250:Steroid Hydroxylases