title: The synthesis of galactopyranosyl derivatives with beta-galactosidases of different origins.
abstract: beta-Galactosidases from four different sources were used to catalyze the transfer of beta-D-galactopyranosyl from 4-nitrophenyl-beta-D-galactopyranoside to a hydroxyl group of 2-acetamido-2-deoxy-galactopyranose in the synthesis of Gal beta (1-3)GalNAc (1), Gal beta (1-4)GalNAc (2) and Gal beta (1-6)GalNAc (3), in triethyl phosphate buffered solutions (20-60%). When beta-galactosidases from Penicillium multicolor and Aspergillus oryzae were used as the catalysts, the beta (1-6)-linked disaccharide was produced as the major product. However, with beta-galactosidase from Bifidobacterium bifidum, the major products were the beta (1-4) and beta (1-6)-linked disaccharides. On the other hand, with beta-galactosidase from Streptococcus 6646K, beta (1-3)-linked disaccharide was predominant together with beta (1-4)-linked isomer. Gal beta (1-3)GlcNAc (4), Gal beta (1-4)GlcNAc (5) and Gal beta (1-6)GlcNAc (6) were also synthesized with beta-galactosidase from S. 6646K and B. bifidum with 2-acetamido-2-deoxy-glucopyranose as the acceptor and PNPGal as the donor. In both cases, the beta (1-4)-linked disaccharide was predominantly produced. In addition, a comparative study was carried out to determine the regioselectivity of the transglycosylation reaction as well as the hydrolytic specificity toward the same linked disaccharides.
authors.affiliation: Meiji Institute of Health Science, Meiji Milk Products Co., Ltd., Odawara, Japan.
authors.forename: J H
authors.initials: JH
authors.lastname: Yoon
authors.forename: K
authors.initials: K
authors.lastname: Ajisaka
mesh_terms: D000116:Acetylgalactosamine / Q000378:metabolism; D000117:Acetylglucosamine / Q000031:analogs & derivatives* / Q000096:biosynthesis; D001419:Bacteria / Q000201:enzymology; D002236:Carbohydrate Conformation; D002851:Chromatography, High Pressure Liquid; D004187:Disaccharides / Q000096:biosynthesis*; D005658:Fungi / Q000201:enzymology; D006031:Glycosylation; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009598:Nitrophenylgalactosides / Q000378:metabolism; D013379:Substrate Specificity; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D004187:Disaccharides; D009598:Nitrophenylgalactosides; C059200:4-nitrophenylgalactoside; C033398:galactosyl-1,3-N-acetylglucosamine; D001616:beta-Galactosidase; D000116:Acetylgalactosamine; D000117:Acetylglucosamine