Structures ofCaulerpaCell Wall Microfibril Xylan with Detection ofβ-1,3-Xylooligosaccharides as Revealed by Matrix-assisted Laser Desorption Ionization/Time of Flight/Mass Spectrometry

Abstract

Since the cell wall microfibril xylans from Caulerpa sp. were not assumed to be constituted from β-1,3-straight chains of homoxylan like Bryopsis maxima but were heteropolysaccharides as glucoxylan or branched structures, identification of its fine structures was desired. Although the results for the linkage analysis were discovered from chemical methods, complementary confirmations were attempted by detection of a series of the β-1,3-xylooligosaccharides prepared as partial acid hydrolysates. Complete separation of the higher oligosaccharide in each was difficult through high performance liquid gel permeation chromatography (GPC), so the composition of oligosaccharides in roughly sub-fractionated samples was detected using matrix-assisted laser desorption ionization/time of flight/mass spectrometry (TOF-MS). By these procedures, it was obvious that cell wall xylan from Caulerpa brachypus was constituted from at least 25 xylose residues of linear oligosaccharides with β-1,3-linkages.Thus the successive me...