The concerted inactivation of Escherichia coli uridine diphosphate galactose 4-epimerase by sugar nucleotide together with a free sugar.
1. The combined effect of the sugar nucleotides UDP-D-fucose or UDP-D-glucuronic acid together with the free sugars D-fucose or L-arabinose is the inactivation of the Escherichia coli enzyme UDP-galactose 4-epimerase (EC 5.1.3.2). The sugar nucleotide or the free sugar alone or the sugar nucleotide plus 5'-Ump do not inactivate the enzyme. 2. The inactivation of the enzyme by its substrate UDP-D-glucose was not affected by the presence of free sugar. 3. In all cases the inactivation observed follows pseudo-first-order kinetics. 4. A comparison of various sugar nucleotides indicates that the hydroxymethyl group at position 6 of the sugar moiety of the natural substrates is important for substrate binding.
D001089:Arabinose / Q000494:pharmacology*; D001665:Binding Sites; D002238:Carbohydrate Epimerases / Q000037:antagonists & inhibitors*; D004926:Escherichia coli / Q000201:enzymology*; D005643:Fucose / Q000494:pharmacology*; D007700:Kinetics; D014534:UDPglucose 4-Epimerase / Q000037:antagonists & inhibitors*; D014500:Uracil Nucleotides / Q000494:pharmacology; D014539:Uridine Diphosphate Sugars / Q000494:pharmacology*
D014500:Uracil Nucleotides; D014539:Uridine Diphosphate Sugars; D005643:Fucose; D001089:Arabinose; D002238:Carbohydrate Epimerases; D014534:UDPglucose 4-Epimerase