title: Enzymic synthesis of lacto-N-triose II and its positional analogues.
abstract: N-acetylhexosaminidase from Nocardia orientalis catalysed the synthesis of lacto-N-triose II glycoside (beta-D-GlcNAc-(1-3)-beta-D-Gal-(1-4)-beta-D-Glc-OMe, 3) with its isomers beta-D-GlcNAc-(1-6)-beta-D-Gal-(1-4)-beta-d-Glc-OMe (4) and beta-D-Gal-(1-4)-[beta-D-GlcNAc-(1-6)]-beta-D-Glc-OMe (5) through N-acetylglucosaminyl transfer from N,N'-diacetylchitobiose (GlcNAc2) to methyl beta-lactoside. The enzyme formed the mixture of trisaccharides 3, 4 and 5 in 17% overall yield based on GlcNAc2, in a ratio of 20:21:59. With p-nitrophenyl beta-lactoside as an acceptor, the enzyme also produced p-nitrophenyl beta-lacto-N-trioside II (beta-D-GlcNAc-(1-3)-beta-D-Gal-(1-4)-beta-D-Glc-OC6H4NO2-p, 6) with its isomers beta-D-GlcNAc-(1-6)-beta-D-Gal-(1-4)-beta-D-Glc-OC6H4NO2-p (7) and beta-D-Gal-(1-4)-[beta-D-GlcNAc-(1-6)]-beta-D-Glc-OC6H4NO2-p (8). In this case, when an inclusion complex of p-nitrophenyl lactoside acceptor with beta-cyclodextrin was used the regioselectivity of glycosidase-catalysed formation of trisaccharide glycoside was substantially changed. It resulted not only in a significant increase of the overall yield of transfer products, but also in the proportion of the desired compound 6.
authors.affiliation: United Graduate School of Agricultural Science, Gifu University, Shizuoka University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Matahira
authors.forename: A
authors.initials: A
authors.lastname: Tashiro
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Kawagishi
authors.forename: T
authors.initials: T
authors.lastname: Usui
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D007202:Indicators and Reagents; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009615:Nocardia / Q000201:enzymology; D009844:Oligosaccharides / Q000138:chemical synthesis*; D014312:Trisaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D001616:beta-Galactosidase / Q000032:analysis / Q000378:metabolism*; D001619:beta-N-Acetylhexosaminidases
chemical_list: D007202:Indicators and Reagents; D009844:Oligosaccharides; D014312:Trisaccharides; C098555:lacto-N-triose II; D001616:beta-Galactosidase; D001619:beta-N-Acetylhexosaminidases