Reference : UDP-N-Acetyl-alpha-D-glucosamine as acceptor substrate of beta-1,4-galactosyltransfer...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
UDP-N-Acetyl-alpha-D-glucosamine as acceptor substrate of beta-1,4-galactosyltransferase. Enzymatic synthesis of UDP-N-acetyllactosamine.
Elling, Lothar [> > > >]
Zervosen, Astrid mailto [Université de Liège - ULg > > Centre de recherches du cyclotron >]
Gallego, Ricardo Gallego [> > > >]
Nieder, Veronika [> > > >]
Malissard, Martine [> > > >]
Berger, Eric G [> > > >]
Vliegenthart, Johannes F. G. [> > > >]
Kamerling, Johannis P. [> > > >]
Glycoconjugate Journal
Kluwer Academic Publishers
Yes (verified by ORBi)
[en] Alkaline Phosphatase/chemistry ; Animals ; Carbohydrate Sequence ; Cattle ; Humans ; Lactalbumin/chemistry ; Magnetic Resonance Spectroscopy ; Mass Spectrometry ; Milk/chemistry ; Milk, Human/chemistry ; Molecular Sequence Data ; N-Acetyllactosamine Synthase/chemistry ; Substrate Specificity ; Uridine Diphosphate N-Acetylglucosamine/chemistry ; Uridine Diphosphate Sugars/chemical synthesis
[en] The capacity of UDP-N-acetyl-alpha-D-glucosamine (UDP-GlcNAc) as an in vitro acceptor substrate for beta-1,4-galactosyltransferase (beta4GalT1, EC from human and bovine milk and for recombinant human beta4GalT1, expressed in Saccharomyces cerevisiae, was evaluated. It turned out that each of the enzymes is capable to transfer Gal from UDP-alpha-D-galactose (UDP-Gal) to UDP-GlcNAc, affording Gal(beta1-4)GlcNAc(alpha1-UDP (UDP-LacNAc). Using beta4GalT1 from human milk, a preparative enzymatic synthesis of UDP-LacNAc was carried out, and the product was characterized by fast-atom bombardment mass spectrometry and 1H and 13C NMR spectroscopy. Studies with all three beta4GalTs in the presence of alpha-lactalbumin showed that the UDP-LacNAc synthesis is inhibited and that UDP-alpha-D-glucose is not an acceptor substrate. This is the first reported synthesis of a nucleotide-activated disaccharide, employing a Leloir glycosyltransferase with a nucleotide-activated monosaccharide as acceptor substrate. Interestingly, in these studies beta4GalT1 accepts an alpha-glycosidated GlcNAc derivative. The results imply that beta4GalT1 may be responsible for the biosynthesis of UDP-LacNAc, previously isolated from human milk.

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