Step-wise enzymatic preparation and structural characterization of singly and doubly substituted arabinoxylo-oligosaccharides with non-reducing end terminal branches

Carbohydr Res. 2008 Dec 8;343(18):3049-57. doi: 10.1016/j.carres.2008.09.013. Epub 2008 Sep 24.

Abstract

Shearzyme (GH10 endo-1,4-beta-D-xylanase) and two different alpha-L-arabinofuranosidases (AXH-m and AXH-d3) were used stepwise to manufacture arabinoxylo-oligosaccharides (AXOS) with alpha-L-Araf (1-->2)-monosubstituted beta-D-Xylp residues or alpha-L-Araf (1-->2)- and (1-->3) doubly substituted beta-D-Xylp residues from wheat arabinoxylan (AX) in a rather straightforward way. Four major AXOS (d-I, d-II, m-I and m-II) were formed in two separate hydrolyses. The AXOS were purified and the structures were confirmed using TLC, HPAEC-PAD, MALDI-TOF-MS and 1D and 2D NMR spectroscopy. The samples were identified as d-I: alpha-L-Araf-(1-->2)-[alpha-L-Araf-(1-->3)]-beta-D-Xylp-(1-->4)-beta-D-Xylp-(1-->4)-D-Xylp, d-II: alpha-L-Araf-(1-->2)-[alpha-L-Araf-(1-->3)]-beta-D-Xylp-(1-->4)-D-Xylp, m-I: alpha-L-Araf-(1-->2)-beta-D-Xylp-(1-->4)-beta-D-Xylp-(1-->4)-D-Xylp and m-II: alpha-L-Araf-(1-->2)-beta-D-Xylp-(1-->4)-D-Xylp. To our knowledge, this is the first report on structural (1)H and (13)C NMR analysis of xylobiose-derived AXOS d-II and m-II. The latter compound has not been reported previously. The doubly substituted AXOS were produced for the first time in good yields, as d-I and d-II corresponded to 11.8 and 5.6 wt% of AX, respectively. Singly alpha-L-Araf (1-->2)-substituted AXOS could also be prepared in similar yields by treating the doubly substituted AXOS further with AXH-d3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabinose / chemistry*
  • Carbohydrate Sequence
  • Chromatography, Thin Layer
  • Glycoside Hydrolases / metabolism*
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Molecular Sequence Data
  • Monosaccharides / analysis
  • Oligosaccharides / chemistry*
  • Oligosaccharides / isolation & purification
  • Oligosaccharides / metabolism*
  • Oxidation-Reduction
  • Triticum / enzymology*

Substances

  • Monosaccharides
  • Oligosaccharides
  • Arabinose
  • Glycoside Hydrolases