Structures of the Arabinoxylo-oligosaccharides from the Hydrolytic Products of Corncob Arabinoxylan by a Xylanase from Streptomyces^†

Abstract

The hydrolysis of corncob arabinoxylan by a Streptomyces xylanase produced several kinds of oligosaccharides containing both arabinose and xylose residues, three of which have been identified as O-β-d-xylopyranosyl-(1→4)-O-[α-l-arabinofuranosyl-(1?3)]-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (A₁X₃II), O-β-d-xylopyranosyl-(1→4)-O-α-d-xylopyranosyl-(1?2)-O-α-l-arabinofuranosyl-(1?3)]-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (A₁X₄I) and O-β-d-xylopyranosyl-(1?2)-O-α-l-arabinofuranosyl-(1?3)-O-β-d-xylopyranosyl-(1→4)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (A₁X₄-II). On the basis of the structures of the above oligosaccharides, the mode of attachment of arabinose residues to xylose residues in the arabinoxylan and the mode of action of the xylanase on the arabinoxylan are discussed.