| Synonyms |
4,4-dimethyl 4-demethylase, 4,4-dimethyl-9beta,19-cyclopropylsterol-4alpha-methyl-oxidase, 4,4-dimethylsterol-4 -methyl-oxidase, 4,4-dimethylsterol-4alpha-methyl oxidase, 4,4-dimethylsterol-oxidase, 4alpha-methyl oxidase, 4alpha-methylsterole-4alpha-methyl oxidase, C4-sterol methyl oxidase, Erg25A, Erg25B, SMO, SMO1, SMO1-1, SMO1-2, SMO1-3, SMO2, sterol C-4 methyl oxidase, sterol methyl oxidase, sterol-4alpha-methyl oxidase, sterol-4alpha-methyl oxidase 1, sterol-4alpha-methyl-oxidase |
| Comments |
This plant enzyme catalyses a step in the biosynthesis of sterols. It acts on the 4¦Á-methyl group of the 4,4-dimethylated intermediate 24-methylenecycloartanol and catalyses three successive oxidations, turning it into a carboxyl group. The carboxylate is subsequently removed by EC 1.1.1.418, plant 3¦Â-hydroxysteroid-4¦Á-carboxylate 3-dehydrogenase (decarboxylating), which also catalyses the epimerization of the remaining 4¦Â-methyl into the 4¦Á position. Unlike the fungal/animal enzyme EC 1.14.18.9, 4¦Á-methylsterol monooxygenase, this enzyme is not able to remove the methyl group from C-4-monomethylated substrates. That activity is performed in plants by a second enzyme, EC 1.14.18.11, plant 4¦Á-monomethylsterol monooxygenase. |
