Enzymes
| UniProtKB help_outline | 9 proteins |
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- Name help_outline UDP-α-D-glucuronate Identifier CHEBI:58052 Charge -3 Formula C15H19N2O18P2 InChIKeyhelp_outline HDYANYHVCAPMJV-LXQIFKJMSA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])(=O)O[C@H]2O[C@@H]([C@@H](O)[C@H](O)[C@H]2O)C([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 107 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP-α-D-galacturonate Identifier CHEBI:57635 Charge -3 Formula C15H19N2O18P2 InChIKeyhelp_outline HDYANYHVCAPMJV-GXNRKQDOSA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])(=O)O[C@H]2O[C@@H]([C@H](O)[C@H](O)[C@H]2O)C([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:11404 | RHEA:11405 | RHEA:11406 | RHEA:11407 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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The biosynthesis of D-galacturonate in plants. Functional cloning and characterization of a membrane-anchored UDP-D-glucuronate 4-epimerase from Arabidopsis.
Moelhoej M., Verma R., Reiter W.-D.
Pectic cell wall polysaccharides owe their high negative charge to the presence of D-galacturonate, a monosaccharide that appears to be present only in plants and some prokaryotes. UDP-D-galacturonate, the activated form of this sugar, is known to be formed by the 4-epimerization of UDP-D-glucuron ... >> More
Pectic cell wall polysaccharides owe their high negative charge to the presence of D-galacturonate, a monosaccharide that appears to be present only in plants and some prokaryotes. UDP-D-galacturonate, the activated form of this sugar, is known to be formed by the 4-epimerization of UDP-D-glucuronate; however, no coding regions for the epimerase catalyzing this reaction have previously been described in plants. To better understand the mechanisms by which precursors for pectin synthesis are produced, we used a bioinformatics approach to identify and functionally express a UDP-D-glucuronate 4-epimerase (GAE1) from Arabidopsis. GAE1 is predicted to be a type II membrane protein that belongs to the family of short-chain dehydrogenases/reductases. The recombinant enzyme expressed in Pichia pastoris established a 1.3:1 equilibrium between UDP-D-galacturonate and UDP-D-glucuronate but did not epimerize UDP-D-Glc or UDP-D-Xyl. Enzyme assays on cell extracts localized total UDP-D-glucuronate 4-epimerase and recombinant GAE1 activity exclusively to the microsomal fractions of Arabidopsis and Pichia, respectively. GAE1 had a pH optimum of 7.6 and an apparent Km of 0.19 mm. The recombinant enzyme was strongly inhibited by UDP-D-Xyl but not by UDP, UDP-D-Glc, or UDP-D-Gal. Analysis of Arabidopsis plants transformed with a GAE1:GUS construct showed expression in all tissues. The Arabidopsis genome contains five GAE1 paralogs, all of which are transcribed and predicted to contain a membrane anchor. This suggests that all of these enzymes are targeted to an endomembrane system such as the Golgi where they may provide UDP-D-galacturonate to glycosyltransferases in pectin synthesis. << Less
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The 4-epimerization and decarboxylation of uridine diphosphate D-glucuronic acid by extracts from Phaseolus aureus seedlings.
FEINGOLD D.S., NEUFELD E.F., HASSID W.Z.
J Biol Chem 235:910-913(1960) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.