Sterol 14-demethylase

Sterol 14-demethylase

In enzymology, a sterol 14-demethylase is an enzyme that catalyzes the chemical reaction

obtusifoliol + 3 O2 + 3 NADPH + 3 H+ rightleftharpoons 4alpha-methyl-5alpha-ergosta-8,14,24(28)-trien-3beta-ol + formate + 3 NADP+ + 4 H2O

The 4 substrates of this enzyme are obtusifoliol, O2, NADPH, and H+, whereas its 4 products are 4alpha-methyl-5alpha-ergosta-8,14,24(28)-trien-3beta-ol, formate, NADP+, and H2O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with NADH or NADPH as one donor, and incorporation of one atom o oxygen into the other donor. The systematic name of this enzyme class is sterol,NADPH:oxygen oxidoreductase (14-methyl cleaving). Other names in common use include obtusufoliol 14-demethylase, lanosterol 14-demethylase, lanosterol 14alpha-demethylase, and sterol 14alpha-demethylase. This enzyme participates in biosynthesis of steroids.

Structural studies

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes , , , , , and .


  • Bak S, Kahn RA, Olsen CE, Halkier BA "Cloning and expression in Escherichia coli of the obtusifoliol 14 alpha-demethylase of Sorghum bicolor (L.) Moench, a cytochrome P450 orthologous to the sterol 14 alpha-demethylases (CYP51) from fungi and mammals". Plant. J. 11 191–201.
  • Aoyama Y, Yoshida Y "Different substrate specificities of lanosterol 14a-demethylase (P-45014DM) of Saccharomyces cerevisiae and rat liver for 24-methylene-24,25-dihydrolanosterol and 24,25-dihydrolanosterol". Biochem. Biophys. Res. Commun. 178 1064–71.
  • Aoyama Y, Yoshida Y "The 4 beta-methyl group of substrate does not affect the activity of lanosterol 14 alpha-demethylase (P-450(14)DM) of yeast: difference between the substrate recognition by yeast and plant sterol 14 alpha-demethylases". Biochem. Biophys. Res. Commun. 183 1266–72.
  • DHR "The removal of the 32-carbon atom as formic acid in cholesterol biosynthesis". J. Chem. Soc. Chem. Commun. 383–385.

External links

Gene Ontology (GO) codes

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