Galactoglucomannan (GGM) from cultures of Nicotiana plumbaginifolia has Man:Glc:Gal:Ara:Xyl in 1.0:1.1:1.0:0.1:0.04 ratio. Linkage analysis contained 4- and 4,6-Manp, 4-Glcp, terminal Galp and 2-Galp, small amounts and terminal Arap and terminal Xylp, and approximately 0.03 mol acetyl per mol of glucosyl residue. Treatment with α- and β-D-galactosidases showed that the majority of the side-chains were either single Galp-α-(1→residues or the disaccharide Galp-β-(1→2)-Galp-α-(1→ linked to O-6 of the 4-Manp residues of the glucomannan backbone. Analysis of the oligosaccharides generated by endo-(1→4)-β-mannanase digestion confirmed that the GGM comprises a backbone of predominantly alternating →4)-D-Manp-β-(1→ and →4)-D-Glcp-β-(1→ branched at O-6 of 65% of the 4-Manp residues. The major oligosaccharide identified was D-Glcp-β-(1→4)-[D-Galp-β-(1→2)-D-Galp-α-(1→6)]-D-Manp-β-(1→4)-D-Glcp-β-(1→4)-[D-Galp-α-(1→6)]-D-Manp-β-(1→(27%), and most of the other oligosaccharides produced in significant quantities were based on this structure.
nuclear magnetic resonance, linkage analysis, galactoglucomannan, plant cell culture, Nicotiana plumbaginifolia, Endo-(l-4)-b-mannanase, Electrospray ionisation-mass spectrometry
NCBI PubMed ID: 9345755Publication DOI: 10.1016/S0008-6215(97)00144-4Journal NLM ID: 0043535Publisher: Elsevier
Institutions: Cooperative Research Centre for Industrial Plant Biopolymers, School of Botany, University of Melbourne, Victoria, Australia
Methods: 13C NMR, 1H NMR, NMR-2D, methylation, GC-MS, ESI-MS, composition analysis, NMR-1D, HPLC, GPC, enzymatic digestion