Structural Characterization of Tissue-Specific Galactan from Flax Fibers by 1H NMR and MALDI TOF Mass Spectrometry

O. Gur’yanov1 #, T. Gorshkova1, M. Kabel2, H. Schols2, and J. E. G. van Dam3

#Phone: (8432) 231-90-41; fax: (8432) 292-73-47; e-mail:
1Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center, Russian Academy of Sciences, p/b 30, Kazan, 420111, Russia
2Laboratory of Food Chemistry, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, Netherlands
3Research Center, Agrotechnology and Food Innovations, Wageningen University, Wageningen, Netherlands
Received: September 11, 2005;  in final form: April 24, 2006

Abstract: A high-molecular-mass polysaccharide galactan (M 2000 kDa) was isolated from flax at the stage of cell wall thickening of the bast fiber development. The polymer structure was studied by 1H NMR spectroscopy and MALDI TOF mass spectrometry. It is built up of Gal (59%), Rha (15%), GalA (23%), and Ara (3%) residues. The galactan backbone consists of successively alternating monomer disaccharide units (→4GalA1→2Rha1→)n and is similar in its structure to the backbone of rhamnogalacturonan-1 (RG-I). Rhamnose residues bear in position 4 β-(1→4)-galactose side chains of various lengths with a polymerization degree of up to 28 or higher. A part of the side chains have branchings.

Key words: galactanLinum usitatissimum L, MALDI TOF MS, plant fibers, rhamnogalacturonan-1

Russian Journal of Bioorganic Chemistry 2006, 32 (6): 558-567