Combination of UDP-Glc(NAc) 4′-epimerase and galactose oxidase in a one-pot synthesis of biotinylated nucleotide sugars

The enzymatic epimerization of uridine 5'-diphospho-alpha-D-glucose (UDP-Glc, 1) and uridine 5'-diphospho-N-acetyl-alpha-D-glucosamine (UDP-GlcNAc, 2) and the subsequent oxidation of uridine 5'-diphospho-alpha-D-galactose (UDP-Gal, 3) and uridine 5'-diphospho-N-acetyl-alpha-D-galactosamine (UDP-GalNAc, 4) were combined with chemical biotinylation with biotin-epsilon-amidocaproylhydrazide in a one-pot synthesis. Analysis by CE and NMR revealed a mixture (1.0:1.4) of the biotinylated nucleotide sugars uridine 5'-diphospho-6-biotin-epsilon-amidocaproylhydrazino-alpha-D-galactose (UDP-6-biotinylGal, 7) and uridine 5'-diphospho-6-biotin-epsilon-amidocaproylhydrazino-alpha-D -glucose (UDP-6-biotinyl-Glc, 9), respectively, in a reaction started with 1. One product, uridine 5'-diphospho-6-biotin-epsilon-amidocaproylhydrazino-N-acetyl-alpha-D-galactosamine (UDP-6-biotinyl-GaINAc, 8) was formed when the reaction was initiated with 2. It could be demonstrated for the first time that a UDP-Glc(NAc) 4'-epimerase (Gne from Campylobacterjejuni) and galactose oxidase from Dactylium dendroides can be used simultaneously in enzymatic catalysis. This is of particular interest since the coaction of an enzyme demanding reductive conditions and an oxygen-dependent oxidase is unexpected.