title: Enzymatic synthesis and characterization of oligosaccharides structurally related to the repeating unit of Pullulan.
abstract: A trisaccharide (Glcalpha1-4Glcalpha1-6Glc) and a tetrasaccharide (Glcalpha1-4Glcalpha1-4Glcalpha1-6Glc) the structures of which are related to that of repeating unit of pullulan have been obtained, exploiting the transglycolytic activity of Aspergillus niger cyclodextrin glucanotransferase. Both products were obtained in one-pot reaction using as a donor the alpha-cyclodextrin and as an acceptor the disaccharide isomaltose. The regioselectivity of the reaction was 85% for the tetrasaccharide and 80% for the trisaccharide. The yield of reaction resulted to be 42% for the synthesis of trisaccharide and 25% for that of tetrasaccharide. Purification of products was performed by size exclusion chromatography and by semipreparative reverse phase HPLC after reversible derivatization with 2-aminopyridine. Structural characterization was performed by capillary electrophoresis, ion-spray mass spectrometry, and by 13C-NMR spectroscopy. A comparison of these results with those obtained by using alpha-D-glucosidase, which had been effective for the synthesis of the disaccharide isomaltose, is reported.
authors.affiliation: Department of Biochemistry, Biophysics and Macromolecular Chemistry, University of Trieste, Via L. Giorgieri 1, Italy. campa@bbcm.units.it
authors.forename: Cristiana
authors.initials: C
authors.lastname: Campa
authors.forename: Amedeo
authors.initials: A
authors.lastname: Vetere
authors.forename: Amelia
authors.initials: A
authors.lastname: Gamini
authors.forename: Ivan
authors.initials: I
authors.lastname: Donati
authors.forename: Sergio
authors.initials: S
authors.lastname: Paoletti
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D003505:Cyclodextrins / Q000737:chemistry; D005936:Glucans / Q000737:chemistry*; D005959:Glucosidases / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism*; D006031:Glycosylation; D007534:Isomaltose / Q000737:chemistry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D047391:alpha-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D005936:Glucans; D009844:Oligosaccharides; D047391:alpha-Cyclodextrins; D007534:Isomaltose; C009109:pullulan; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; D005959:Glucosidases; C032613:alpha-cyclodextrin