ENZYME entry: EC 1.14.13.246
Accepted Name |
4-beta-methylsterol monooxygenase.
|
Reaction catalysed |
A 3-beta-hydroxy-4,4-dimethylsteroid + 3 NADH + 3 O(2) <=> a 3-beta-hydroxy-4-beta-carboxy-4-alpha-methylsteroid + 3 NAD(+) + 4 H(2)O |
Comment(s) |
- Contains a Rieske [2Fe-2S] iron-sulfur cluster.
- This bacterial enzyme (SdmA) participates in the biosynthesis of
bacterial sterols.
- Together with SdmB it forms an enzyme system that removes one methyl
group from the C-4 position of 4,4-dimethylated steroid molecules.
- SdmA catalyzes three successive oxidations of the C-4-beta methyl
group, turning it into a carboxylate group; the second enzyme, SdmB,
is a bifunctional enzyme that catalyzes two different activities.
- As EC 1.1.1.417 it catalyzes an oxidative decarboxylation that
results in reduction of the 3-beta-hydroxy group at the C-3 carbon to
an oxo group.
- As EC 1.1.1.270 it reduces the 3-oxo group back to a 3-beta-hydroxyl.
- Unlike the animal/fungal enzyme EC 1.14.18.9 and the plant enzymes
EC 1.14.18.10 and EC 1.14.18.11, this enzyme acts preferentially on
the 4-beta-methyl group.
- Since no epimerization of the remaining C-4-alpha methyl group
occurs, the enzyme can only remove one methyl group, leaving a
4-alpha-monomethylated product.
|
Cross-references |
BRENDA | 1.14.13.246 |
EC2PDB | 1.14.13.246 |
ExplorEnz | 1.14.13.246 |
PRIAM enzyme-specific profiles | 1.14.13.246 |
KEGG Ligand Database for Enzyme Nomenclature | 1.14.13.246 |
IUBMB Enzyme Nomenclature | 1.14.13.246 |
IntEnz | 1.14.13.246 |
MEDLINE | Find literature relating to 1.14.13.246 |
MetaCyc | 1.14.13.246 |
Rhea expert-curated reactions | 1.14.13.246 |
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