title: Synthesis of Gal beta 1-3GlcNAc and Gal beta 1-3GlcNAc beta-SEt by an enzymatic method comprising the sequential use of beta-galactosidases from bovine testes and Escherichia coli.
abstract: Gal beta 1-3GlcNAc (1) and Gal beta 1-3GlcNAc beta-SEt (2) were synthesized on a 100 mg scale by the transgalactosylation reaction of bovine testes beta-galactosidase with lactose as donor and N-acetylglucosamine and GlcNAc beta-SEt as acceptors. In both cases the product mixtures contained unwanted isomers and were treated with beta-galactosidase from Escherichia coli which has a different specificity, under conditions favouring hydrolysis, yielding besides the desired products, monosaccharides and traces of trisaccharides. The products were purified to greater than 95% by gel filtration, with a final yield of 12% of 1 and 17% of 2, based on added acceptor. In a separate experiment Gal beta 1-6GlcNAc beta-SEt (3) was synthesized by the transglycosylation reaction using beta-galactosidase from Escherichia coli. No other isomers were detected. Compound 3 was purified by HPLC.
authors.affiliation: Department of Pure and Applied Biochemistry, University of Lund, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Hedbys
authors.forename: E
authors.initials: E
authors.lastname: Johansson
authors.forename: K
authors.initials: K
authors.lastname: Mosbach
authors.forename: P O
authors.initials: PO
authors.lastname: Larsson
authors.forename: A
authors.initials: A
authors.lastname: Gunnarsson
authors.forename: S
authors.initials: S
authors.lastname: Svensson
authors.forename: H
authors.initials: H
authors.lastname: Lönn
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides / Q000138:chemical synthesis*; D004926:Escherichia coli / Q000201:enzymology*; D007202:Indicators and Reagents; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008969:Molecular Sequence Data; D013737:Testis / Q000201:enzymology*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004187:Disaccharides; D007202:Indicators and Reagents; D001616:beta-Galactosidase