title: Enzymatic synthesis of a library of beta-(1-->4) hetero- D-glucose and D-xylose-based oligosaccharides employing cellodextrin phosphorylase.
abstract: Enzymatic synthesis was attempted of six trisaccharides and 14 tetrasaccharides comprising beta-(1-->4)-linked D-glucose and D-xylose residues, using cellodextrin phosphorylase (CDP, EC 2.4.1.49) as the enzyme catalyst, with alpha-D-glucose 1-phosphate (1) or alpha-D-xylose 1-phosphate (2) as the donor substrates, and cellobiose (3), xylobiose (4), betaGlc-(1-->4)-Xyl (5), or betaXyl-(1-->4)-Glc (6) as the acceptor substrates. All enzymatic reactions were performed at pH 7.0 and the products purified by gel-filtration chromatography. We successfully synthesized all six hetero-trisaccharides and 10 of the 14 possible hetero-tetrasaccharides. It was not found possible to synthesize the four tetrasaccharides with a Xyl-->Glc sequence at their non-reducing ends employing this method. The stereochemistries of the isolated products were assessed by analysis of their 2D NMR spectra (DQF-COSY, TOCSY, HSQC, HMBC), confirming that all of the glycosidic bonds in the products were beta-(1-->4) linkages.
mesh_terms: D002240:Carbohydrate Sequence; D002247:Carbon Isotopes; D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D014316:Tritium; D014994:Xylose / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D009844:Oligosaccharides; D014316:Tritium; D014994:Xylose; D005964:Glucosyltransferases; C105024:cellodextrin phosphorylase; D005947:Glucose