| 英文名 |
3beta-hydroxysteroid-4alpha-carboxylate 3-dehydrogenase (decarboxylating) |
| Example Structure |
 |
| 别名 |
3beta-hydroxy-4alpha-methylcholestenecarboxylate 3-dehydrogenase (decarboxylating), 3beta-hydroxy-4beta-methylcholestenoate dehydrogenase, 4alpha-carboxylic acid decarboxylase, C-3 sterol dehydrogenase(C-4 decarboxylase), Erg26, Erg26p, NSDHL, sterol 4alpha-carboxylic decarboxylase, sterol-4-alpha-carboxylate 3-dehydrogenase, sterol-4-alpha-carboxylate-3-dehydrogenase, sterol-4alpha-carboxylate 3-dehydrogenase |
| EC Number |
1.1.1.170 |
| CAS编号 |
71822-23-6 |
| Comments |
The enzyme participates in the biosynthesis of several important sterols such as ergosterol and cholesterol. It is part of a three enzyme system that removes methyl groups from the C-4 position of steroid molecules. The first enzyme, EC 1.14.18.9, 4¦Á-methylsterol monooxygenase, catalyses three successive oxidations of the methyl group, resulting in a carboxyl group; the second enzyme, EC 1.1.1.170, catalyses an oxidative decarboxylation that results in a reduction of the 3¦Â-hydroxy group at the C-3 carbon to an oxo group; and the last enzyme, EC 1.1.1.270, 3¦Â-hydroxysteroid 3-dehydrogenase, reduces the 3-oxo group back to a 3¦Â-hydroxyl. If a second methyl group remains at the C-4 position, this enzyme also catalyses its epimerization from 4¦Â to 4¦Á orientation, so it could serve as a substrate for a second round of demethylation. cf. EC 1.1.1.418, plant 3¦Â-hydroxysteroid-4¦Á-carboxylate 3-dehydrogenase (decarboxylating). |
| Cofactor |
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| History |
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| Reactions |
A 3-beta-hydroxysteroid-4-alpha-carboxylate + NAD(P)(+) = a 3-oxosteroid + CO(2) + NAD(P)H. |
