Abstract
Uridine diphosphate (UDP)-glucose 4-epimerase (EC 5.1.3.2) has been purified over 1000-fold from extracts of wheat germ by MnCl2 treatment, (NH4)2SO4 fractionation, Sephadex column chromatography, and adsorption onto and elution from calcium phosphate gel. The enzyme has a pH optimum of 9.0. Km values are 0.1 mm for UDP-d-galactose and 0.2 mm for UDP-d-glucose. NAD is required for activity; Ka = 0.04 mm. NADH is an inhibitor strictly competitive with NAD; Ki = 2 μm. Wheat germ also contains UDP-l-arabinose 4-epimerase (EC 5.1.3.5) and thymidine diphosphate (TDP)-glucose 4-epimerase which are distinct from UDP-glucose 4-epimerase.
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Selected References
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- Ankel H., Feingold D. S. Biosynthesis of uridine diphosphate D-xylose. II. Uridine diphosphate D-glucuronate carboxy-lyase of Cryptococcus laurentii. Biochemistry. 1966 Jan;5(1):182–189. doi: 10.1021/bi00865a024. [DOI] [PubMed] [Google Scholar]
- Ankel H., Maitra U. S. Epimerization of UDP-glucose and UDP-xylose in Escherichia coli: evidence for a single enzyme. Biochem Biophys Res Commun. 1968 Aug 13;32(3):526–532. doi: 10.1016/0006-291x(68)90694-3. [DOI] [PubMed] [Google Scholar]
- Darrow R. A., Rodstrom R. Purification and properties of uridine diphosphate galactose 4-epimerase from yeast. Biochemistry. 1968 May;7(5):1645–1654. doi: 10.1021/bi00845a005. [DOI] [PubMed] [Google Scholar]
- FEINGOLD D. S., NEUFELD E. F., HASSID W. Z. The 4-epimerization and decarboxylation of uridine diphosphate D-glucuronic acid by extracts from Phaseolus aureus seedlings. J Biol Chem. 1960 Apr;235:910–913. [PubMed] [Google Scholar]
- LELOIR L. F. The enzymatic transformation of uridine diphosphate glucose into a galactose derivative. Arch Biochem Biophys. 1951 Sep;33(2):186–190. doi: 10.1016/0003-9861(51)90096-3. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- MAXWELL E. S. The enzymic interconversion of uridine diphosphogalactose and uridine diphosphoglucose. J Biol Chem. 1957 Nov;229(1):139–151. [PubMed] [Google Scholar]
- NEUFELD E. F., GINSBURG V., PUTMAN E. W., FANSHIER D., HASSID W. Z. Formation and interconversion of sugar nucleotides by plant extracts. Arch Biochem Biophys. 1957 Jul;69:602–616. doi: 10.1016/0003-9861(57)90524-6. [DOI] [PubMed] [Google Scholar]
- Robinson E. A., Kalckar H. M., Troedsson H., Sanford K. Metabolic inhibition of mammalian uridine diphosphate galactose 4-epimerase in cell cultures and in tumor cells. J Biol Chem. 1966 Jun 25;241(12):2737–2745. [PubMed] [Google Scholar]
- Salo W. L., Nordin J. H., Peterson D. R., Bevill R. D., Kirkwood S. The specificity of UDP-glucose 4-epimerase from the yeast Saccharomyces fragilis. Biochim Biophys Acta. 1968 Feb 5;151(2):484–492. doi: 10.1016/0005-2744(68)90116-2. [DOI] [PubMed] [Google Scholar]
- WILSON D. B., HOGNESS D. S. THE ENZYMES OF THE GALACTOSE OPERON IN ESCHERICHIA COLI. I. PURIFICATION AND CHARACTERIZATION OF URIDINE DIPHOSPHOGALACTOSE 4-EPIMERASE. J Biol Chem. 1964 Aug;239:2469–2481. [PubMed] [Google Scholar]
- Zalitis J., Feingold D. S. The mechanism of action of UDPG dehydrogenase. Biochem Biophys Res Commun. 1968 Jun 10;31(5):693–698. doi: 10.1016/0006-291x(68)90617-7. [DOI] [PubMed] [Google Scholar]
