Uridine Diphosphate Galacturonate 4-Epimerase from the Blue-Green Alga Anabaena flos-aquae
| Autor: | Utpalendu S. Maitra, Mary A. Gaunt, Helmut Ankel |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
chemistry.chemical_classification
biology Anabaena Stereochemistry Allosteric regulation Substrate (chemistry) Cooperativity Cell Biology biology.organism_classification Biochemistry carbohydrates (lipids) Uridine diphosphate chemistry.chemical_compound Enzyme chemistry Uridine Diphosphate Sugars Molecular Biology Uracil nucleotide |
| Zdroj: | Journal of Biological Chemistry. 249:2366-2372 |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/s0021-9258(19)42739-7 |
| Popis: | Epimerization of UDP-glucuronate to UDP-galacturonate in the blue-green alga Anabaena flos-aquae is catalyzed by an enzyme distinct from UDP-galactose 4-epimerase. Partially purified UDP-galacturonate 4-epimerase from this organism has the following characteristics: Km for UDP-glucuronate, 37 µm; pH optimum, 8.5; equilibrium constant (in the direction of UDP-galacturonate formation), 2.6; approximate molecular weight, 54,000. DPN, TPN, and UDP-glucose are inhibitors competitive with substrate. UMP- and UDP-xylose are allosteric inhibitors with Hill constants of 1.6 and 2.1. These data suggest homotropic cooperativity in the binding of at least 2 inhibitor molecules to the enzyme. |
| Databáze: | OpenAIRE |
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