title: Enzymatic synthesis of sulfated disaccharides using beta-D-galactosidase-catalyzed transglycosylation.
abstract: We have established a unique enzymatic approach for obtaining sulfated disaccharides using Bacillus circulans beta-D-galactosidase-catalyzed 6-sulfo galactosylation. When 4-methyl umbelliferyl 6-sulfo beta-D-galactopyranoside (S6Gal beta-4MU) was used as a donor, the enzyme induced transfer of 6-sulfo galactosyl residue to GlcNAc acceptor. As a result, the desired compound 6'-sulfo N-acetyllactosamine (S6Gal beta1-4GlcNAc) and its positional isomer 6'-sulfo N-acetylisolactosamine (S6Gal beta1-6GlcNAc) were observed by HPAEC-PAD, in 49% total yield based on the donor added, and in a molar ratio of 1:3.5. With a glucose acceptor, the regioselectivity was substantially changed and S6Gal beta1-2Glc was mainly produced along with beta-(1-1)alpha, beta-(1-3), beta-(1-6) isomers in 74% total yield. When methyl alpha-D-glucopyranoside (Glc alpha-OMe) was an acceptor, the enzyme also formed mainly S6Gal beta1-2Glc alpha-OMe with its beta-(1-6)-linked isomer in 41% total yield based on the donor added. In both cases, it led to the predominant formation of beta-(1-2)-linked disaccharides. In contrast, with the corresponding methyl beta-D-glucopyranoside (Glc beta-OMe) acceptor, S6Gal beta1-3Glc beta-OMe and S6Gal beta1-6Glc beta-OMe were formed in a low total yield of 12%. These results indicate that the regioselectivity and efficiency on the beta-D-galactosidase-mediated transfer reaction significantly depend on the anomeric configuration in the glucosyl acceptors.
authors.affiliation: Department of Applied Biological Chemistry, Shizuoka University, Japan. actmura@agr.shizuoka.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Murata
authors.forename: M
authors.initials: M
authors.lastname: Kosugi
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Urashima
authors.forename: T
authors.initials: T
authors.lastname: Usui
mesh_terms: D001407:Bacillus / Q000201:enzymology; D004187:Disaccharides / Q000096:biosynthesis* / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology; D006001:Glycoconjugates / Q000096:biosynthesis / Q000737:chemistry; D006031:Glycosylation; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013463:Sulfuric Acid Esters / Q000737:chemistry / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D004187:Disaccharides; D006001:Glycoconjugates; D013463:Sulfuric Acid Esters; D001616:beta-Galactosidase