CYP27A1

(redirected from 25-hydroxylase)

CYP27A1

A gene on chromosome 2q33-qter that encodes a member of the cytochrome P450 superfamily of enzymes, which catalyse reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP27A1 is a mitochondrial protein that oxidises cholesterol intermediates as part of the bile-synthesis pathway. It catalyses the first step in the oxidation of the side chain of sterol intermediates and has a vitamin D3-25-hydroxylase activity. Because the conversion of cholesterol to bile acids is the major route for eliminating cholesterol from the body, CYP27A1 is important for cholesterol homeostasis.

Molecular pathology
CYP27A1 mutations cause cerebrotendinous xanthomatosis.
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References in periodicals archive ?
1-[alpha]-hydroxylase (CYP27B1) and 25-hydroxylase convert vitamin D to its active form, 1,25 dihydroxy-vitamin [D.
It is basically a hormone obtained after hydroxylation at carbon number 25 by enzyme 25-hydroxylase in the liver to form 25-hydroxyvitamin D, followed by another hydroxylation at carbon number 1 by the enzyme 1a hydroxylase to form, 1,25-dihydroxyvitamin D, active form vitamin D.
Genetic evidence that the human CYP2R1 enzyme is a key vitamin D 25-hydroxylase.
Microsomal enzyme vitamin D 25-hydroxylase work as catalyst in this reaction, this enzyme is formed by hepatocytes, when calcidiol are prepared, the creation is unconfined in the blood plasma, wherever it will make binding with vitamin D binding protein is called a-globulin [24].
10 demonstrated the inhibition by PIs of the 25-hydroxylase and the 1a-hydroxylase involved in vitamin D metabolism.
Porcine microsomal vitamin D(3) 25-hydroxylase (CYP2D25).
In addition, there is reason to believe that 25(OH)D is a marker both of gonadal function (vitamin D is 25-hydroxylated by gonadal tissues) and of the capacity of the liver to detoxify xenobiotics (hepatic 25-hydroxylase enzymes are also involved in phase 1 detoxification pathways).
From here, vitamin D3 is transported to your liver, where it is combined with the 25-hydroxylase enzyme to form calcidiol (25-hydroxycholecalciferol or 25-hydroxyvitamin D).
3; at this point, the V(max) of the 25-hydroxylase appeared to be achieved.
This occurs because at high vitamin D concentrations, hepatic 25-hydroxylases become saturated and the reaction switches from first order to zero order.