Oxysterol biosynthetic enzymes

Biochim Biophys Acta. 2000 Dec 15;1529(1-3):126-35. doi: 10.1016/s1388-1981(00)00142-6.


Oxysterols, herein defined as derivatives of cholesterol with a hydroxyl group on the side chain, play several roles in lipid metabolism. Members of this class regulate the expression of genes that participate in both sterol and fat metabolism, serve as substrates for the synthesis of bile acids, and are intermediates in the transfer of sterols from the periphery to the liver. Three abundant naturally occurring oxysterols are 24-hydroxycholesterol, 25-hydroxycholesterol, and 27-hydroxycholesterol. The cholesterol hydroxylase enzymes that synthesize each of these have been isolated over the last several years and their study has produced insight into the biology of oxysterols. This article focuses on the properties of these enzymes.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Bile Acids and Salts / metabolism
  • Biological Transport
  • Cholestanetriol 26-Monooxygenase
  • Cholesterol 24-Hydroxylase
  • Cloning, Molecular
  • Cytochrome P-450 Enzyme System / chemistry
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism*
  • DNA, Complementary / isolation & purification
  • Humans
  • Hydroxycholesterols / chemistry
  • Liver / metabolism*
  • Molecular Structure
  • Steroid Hydroxylases / chemistry
  • Steroid Hydroxylases / genetics
  • Steroid Hydroxylases / metabolism*
  • Sterols / biosynthesis*
  • Sterols / chemistry


  • Bile Acids and Salts
  • DNA, Complementary
  • Hydroxycholesterols
  • Sterols
  • 24-hydroxycholesterol
  • 27-hydroxycholesterol
  • 25-hydroxycholesterol
  • Cytochrome P-450 Enzyme System
  • Steroid Hydroxylases
  • Cholesterol 24-Hydroxylase
  • CYP27A1 protein, human
  • Cholestanetriol 26-Monooxygenase