EC - Cholesterol 25-monooxygenase

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IntEnz Enzyme Nomenclature


Accepted name:
cholesterol 25-monooxygenase
Other name:
cholesterol 25-hydroxylase [ambiguous]
Systematic name:
cholesterol,hydrogen-donor:oxygen oxidoreductase (25-hydroxylating)




Unlike most other sterol hydroxylases, this enzyme is not a cytochrome P450. Instead, it uses diiron cofactors to catalyse the hydroxylation of hydrophobic substrates [1]. The diiron cofactor can be either Fe-O-Fe or Fe-OH-Fe and is bound to the enzyme through interactions with clustered histidine or glutamate residues [4,5]. In cell cultures, this enzyme down-regulates cholesterol synthesis and the processing of sterol regulatory element binding proteins (SREBPs). cf. EC, cholesterol C-25 hydroxylase.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0001567


  1. Lund, E.G., Kerr, T.A., Sakai, J., Li, W.-P. and Russell, D.W.
    cDNA cloning of mouse and human cholesterol 25-hydroxylases, polytopic membrane proteins that synthesize a potent oxysterol regulator of lipid metabolism.
    J. Biol. Chem. 273 : 34316-34327 (1998). [PMID: 9852097]
  2. Chen, J.-J., Lukyanenko, Y. and Hutson, J.C.
    25-hydroxycholesterol is produced by testicular macrophages during the early postnatal period and influences differentiation of Leydig cells in vitro.
    Biol. Reprod. 66 : 1336-1341 (2002). [PMID: 11967195]
  3. Lukyanenko, Y., Chen, J.-J. and Hutson, J.C.
    Testosterone regulates 25-hydroxycholesterol production in testicular macrophages.
    Biol. Reprod. 67 : 1435-1438 (2002). [PMID: 12390873]
  4. Fox, B.G., Shanklin, J., Ai, J., Loehr, T.M. and Sanders-Loehr, J.
    Resonance Raman evidence for an Fe-O-Fe center in stearoyl-ACP desaturase. Primary sequence identity with other diiron-oxo proteins.
    Biochemistry 33 : 12776-12786 (1994). [PMID: 7947683]
  5. Russell, D.W.
    The enzymes, regulation, and genetics of bile acid synthesis.
    Annu. Rev. Biochem. 72 : 137-174 (2003). [PMID: 12543708]

[EC created 2005, modified 2020]