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ENZYME

ENZYME entry: EC 1.14.18.9

Accepted Name
4alpha-methylsterol monooxygenase
Alternative Name(s)
4-methylsterol oxidase
methylsterol hydroxylase
methylsterol monooxygenase
Reaction catalysed
4,4-dimethyl-5alpha-cholest-7-en-3beta-ol + 6 Fe(II)-[cytochrome b5] + 5 H(+) + 3 O2 = 4alpha-carboxy-4beta-methyl-5alpha-cholest-7-ene-3beta-ol + 6 Fe(III)-[cytochrome b5] + 4 H2O
Comment(s)
  • This enzyme is found in fungi and animals and catalyzes a step in the biosynthesis of important sterol molecules such as ergosterol and cholesterol, respectively.
  • The enzyme acts on the 4alpha-methyl group.
  • Subsequent decarboxylation by EC 1.1.1.170 occurs concomitantly with epimerization of the remaining 4beta-methyl into the 4alpha position, thus making it a suitable substrate for a second round of catalysis. cf. EC 1.14.13.246, EC 1.14.18.10 and EC 1.14.18.11.
  • Formerly EC 1.14.13.72 and EC 1.14.99.16.
Cross-references
BRENDA1.14.18.9
EC2PDB1.14.18.9
ExplorEnz1.14.18.9
PRIAM enzyme-specific profiles1.14.18.9
KEGG Ligand Database for Enzyme Nomenclature1.14.18.9
IUBMB Enzyme Nomenclature1.14.18.9
IntEnz1.14.18.9
MEDLINEFind literature relating to 1.14.18.9
MetaCyc1.14.18.9
Rhea expert-curated reactions1.14.18.9
UniProtKB/Swiss-Prot
O59933, ERG25_CANALQ5ZLL6, MSMO1_CHICKQ7ZW77, MSMO1_DANRE
Q15800, MSMO1_HUMANQ4R4Q4, MSMO1_MACFAQ9CRA4, MSMO1_MOUSE
Q6UGB2, MSMO1_PIGQ5R574, MSMO1_PONABO35532, MSMO1_RAT
Q55D52, MSMOA_DICDIQ55D54, MSMOB_DICDIQ8L7W5, SMO11_ARATH
Q1EC69, SMO12_ARATHF4JLZ6, SMO13_ARATHQ9ZW22, SMO21_ARATH
Q8VWZ8, SMO22_ARATH

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