Enzyme‐aided construction of medium‐sized alditols of complete O‐linked saccharides

Abstract

We have constructed by enzyme-aided in vitro synthesis a hexasaccharide alditol Galβ1—4GlcNAcβ1—6Galβ1—4GlcNAcβ1—6(Galβ1—3)GalNAc-ol and shown that it resists the action of endo-β-galactosidase from Bacteroides fragilis under conditions where a related pentasaccharide alditol, GlcNAcβ1—3Galβ1—4GlcNAcβ1—6(Galβ1—3)GalNAc-ol, was completely cleaved. Together with earlier results from this laboratory, our present data imply that endo-β-galactosidase from B. fragilis, apparently, can be used to distinguish between GlcNAcβ1—6Gal and GlcNAcβ1—3Gal units within linear backbone sequences of all known types of oligo-(N-acetyllactosamino)glycans.