title: Enzymic alpha-galactosylation of a cyclic glucotetrasaccharide derived from alternan.
abstract: Alternanase catalyzes the hydrolysis of alternan, an alpha-(1-->3)-alpha-(1-->6)-D-glucan produced by Leuconostoc mesenteroides, resulting in the formation of a cyclic tetramer cyclo -->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->(2) (cGlc(4)). Two alpha-galactosidases, one from coffee bean and the other produced by a fungus, currently described as Thermomyces lanuginosus, were found to catalyze an efficient 6-O-alpha-D-galactopyranosylation of cGlc(4). The attachment of a nonreducing alpha-D-galactopyranosyl residue to the cGlc(4) molecule opens new possibilities for future applications of the cyclic tetramer, since the D-galactopyranosyl residue can be easily modified by D-galactose oxidase to introduce a reactive aldehyde group. The results also extend our knowledge about the synthetic potential of T. lanuginosus alpha-galactosidase.
authors.affiliation: Institute of Chemistry, Slovak Academy of Sciences, 842 38, Bratislava, Slovak Republic.
authors.forename: P
authors.initials: P
authors.lastname: Biely
authors.forename: V
authors.initials: V
authors.lastname: Puchart
authors.forename: G L
authors.initials: GL
authors.lastname: Cote
mesh_terms: D002240:Carbohydrate Sequence; D003069:Coffee / Q000201:enzymology; D005658:Fungi / Q000201:enzymology; D005936:Glucans / Q000737:chemistry* / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D007934:Leuconostoc / Q000737:chemistry / Q000201:enzymology; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009844:Oligosaccharides / Q000378:metabolism*; D000519:alpha-Galactosidase / Q000378:metabolism*
chemical_list: D003069:Coffee; D005936:Glucans; D009844:Oligosaccharides; C439358:alternan; C439359:cyclic glucotetrasaccharide; D006026:Glycoside Hydrolases; C091143:alternanase; D000519:alpha-Galactosidase