Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

cholestanetriol 26-monooxygenase

Name from literature

sterol 27-hydroxylase

Pathway from literature

the alternative pathway

Pathway from KEGG

Lipid Metabolism; Bile acid biosynthesis; map00120

Cellular Processes; Endocrine System; PPAR signaling pathway; map03320


Rat (10116)

Genome localization

9q33[301517 ],


Requires ferrodoxin. Acts on cholesterol, cholest-5-en-3beta,7alpha-diol, 7alpha-hydroxycholest-4-en-3-one, 5beta-cholestane-3alpha,7alpha-diol as well as 5beta-cholestane-3alpha,7alpha,12alpha-triol. With cholesterol as well as 26-hydroxycholesterol, 24-hydroxy- and 25-hydroxycholesterol are also formed. With prolonged treatment, 26-hydroxycholesterol is converted into the corresponding 27-aldehyde and 27-oic acid.

Rate-limiting Description

"They are cholesterol 7alpha-hydroxylase (CYP7A1), the rate limiting enzyme in the classic pathway, sterol 12alpha-hydroxylase (CYP8B1), the key enzyme for synthesis of cholic acid (CA), and sterol 27-hydroxylase (CYP27), the initial enzyme in the alternative pathway." (15936349)

Gene ontology

Gene ontology

GO:0047749 (F) cholestanetriol 26-monooxygenase activity [P17178 ];
GO:0009055 (F) electron carrier activity [P17178 ];
GO:0055114 (P) oxidation reduction [P17178 ];
GO:0020037 (F) heme binding [P17178 ];
GO:0005506 (F) iron ion binding [P17178 ];

Subcellular localization


mitochondrion [P17178 ];




Entrez Gene


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  Last Modified: 2009-03-24  
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