title: Trisaccharide synthesis by glycosyl transfer from p-nitrophenyl beta-D-N-acetylgalactosaminide on to disaccharide acceptors catalysed by the beta-N-acetylhexosaminidase from Aspergillus oryzae.
abstract: The beta-N-acetylhexosaminidase from Aspergillus oryzae catalysed the transfer of beta-D-N-acetylgalactosaminyl residues from p-nitrophenyl beta-D-N-acetylglucosaminide on to disaccharide acceptors consisting of thioethyl glycosides of alpha-D-Glc-(1-->4)-beta-D-Glc, beta-D-Glc-(1-->4)-beta-D-Glc and beta-D-Glc-(1-->6)-beta-D-Glc. The principle of 'anomeric control' was exemplified by the results which showed that an alpha-linkage between the units of the acceptor favoured exclusively the formation of a new (1-->4)-linkage, whereas the beta-configuration in the acceptor led to a mixture of (1-->4)- and (1-->3)-linked products, as observed for simple glycosides of monosaccharide acceptors. With the thioethyl beta-lactoside as acceptor, beta-D-Gal-(1-->6)-beta-D-Gal-(1-->4)-beta-D-GlcSEt was formed, owing to the action of residual beta-D-galactosidase activity in the N-acetylhexosaminidase on the thioethyl beta-lactoside acting as both donor and acceptor.
authors.affiliation: Department of Chemistry, University of Warwick, Coventry, UK.
authors.forename: S
authors.initials: S
authors.lastname: Singh
authors.forename: M
authors.initials: M
authors.lastname: Scigelova
authors.forename: P
authors.initials: P
authors.lastname: Critchley
authors.forename: D H
authors.initials: DH
authors.lastname: Crout
mesh_terms: D000116:Acetylgalactosamine / Q000031:analogs & derivatives* / Q000378:metabolism; D001236:Aspergillus oryzae / Q000201:enzymology*; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D006027:Glycosides / Q000138:chemical synthesis; D006596:Hexosaminidases / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D014312:Trisaccharides / Q000138:chemical synthesis*
chemical_list: D004187:Disaccharides; D006027:Glycosides; D014312:Trisaccharides; C014123:4-nitrophenyl-2-acetamido-2-deoxygalactopyranoside; D006596:Hexosaminidases; D005947:Glucose; D000116:Acetylgalactosamine