Related Experiment Video
Updated: Oct 1, 2026

Metabolic Glycoengineering of Sialic Acid Using N-acyl-modified Mannosamines
Published on: November 25, 2017
Several polylactosamine-modifying glycosyltransferases also use internal GalNAcbeta1-4GlcNAc units of synthetic
Hanna Salo1, Olli Aitio, Kristiina Ilves
1Institute of Biotechnology, Laboratory of Glycobiology, FIN-00014 University of Helsinki, Finland.
Abstract:
The GalNAcbeta1-4GlcNAc determinant (LdN) occurs in some human and bovine glycoconjugates and also in lower vertebrates and invertebrates. It has been found in unsubstituted as well as terminally substituted forms at the distal end of conjugated glycans, but it has not been reported previously at truly internal positions of polylactosamine chains. Here, we describe enzyme-assisted conversion of LdNbeta1-OR oligosaccharides into GlcNAcbeta1-3GalNAcbeta1-4GlcNAcbeta1-OR. The extension reactions, catalyzed by human serum, were modeled after analogous beta3-GlcNAc transfer processes that generate GlcNAcbeta1-3Galbeta1-4GlcNAcbeta1-OR. The newly synthesized GlcNAcbeta1-3GalNAc linkages were unambiguously identified by nuclear magnetic resonance data, including the appropriate long-range correlations in heteronuclear multiple bond correlation spectra. The novel GlcNAcbeta1-3'LdN determinant proved to be a functional acceptor for several mammalian glycosyltransferases, suggesting that human polylactosamines may contain internal LdN units in many distinct forms. The GlcNAcbeta1-3'LdN determinant was unusually resistant toward jackbean beta-N-acetylhexosaminidase; the slow degradation should lead to a convenient method for the search of putative internal LdN determinants in natural polylactosamine chains.
Related Concept Videos
Oligosaccharide Assembly
Multiple sugar molecules that may or may...
Protein Glycosylation
Glycosylation occurs in...
Proteoglycans
Biosynthesis of Polysaccharides
Protein Folding Quality Check in the RER
Glucose Transporters
Facilitated diffusion-glucose transporters (GLUTs) are encoded by the solute-linked carrier (SLC) family 2, subfamily A gene family, or SLC2A. The 14 GLUT protein members are distributed into three classes:

