4-O-methyl-beta-L-idopyranosyluronic acid linked to xylan from kraft pulp: isolation procedure and characterisation by NMR spectroscopy.
The tetrasaccharide 2"-O-(4-O-methyl-beta-L-idopyranosyluronic acid)xylotriose was isolated from enzymatically hydrolysed, unbleached, birch kraft pulp by anion-exchange chromatography in two steps. The primary structure of the tetrasaccharide was determined by 1H and 13C NMR spectroscopy, using homonuclear and heteronuclear two-dimensional techniques. NOE data and 3JH,H coupling constants show that the 4-O-methyl-beta-L-idopyranosyluronic acid in the tetrasaccharide is predominantly in the 1C4 chair conformation. The pKa value (3.17) for 4-O-methyliduronic acid attached beta-(1-->2) to xylose was determined from the pH-dependent chemical shift of H-5. The amount of 4-O-methyliduronic acid (0.1-0.5 mol%) in surface xylan of unbleached birch and pine kraft pulps was determined by extensive xylanase treatment and further analysis by NMR spectroscopy and high-performance anion-exchange chromatography.
Technical Research Centre of Finland, Finland.
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A
Teleman
M
M
Siika-aho
H
H
Sorsa
J
J
Buchert
M
M
Perttula
T
T
Hausalo
M
M
Tenkanen
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D007067:Iduronic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009005:Monosaccharides / Q000032:analysis; D009844:Oligosaccharides / Q000737:chemistry*; D014574:Uronic Acids / Q000737:chemistry* / Q000302:isolation & purification*; D014934:Wood; D014990:Xylans / Q000737:chemistry*
C103124:4-O-methylidopyranosyluronic acid; D009005:Monosaccharides; D009844:Oligosaccharides; D014574:Uronic Acids; D014990:Xylans; D007067:Iduronic Acid