<Original>Studies on Hemicelluloses in Tension Wood : II. Structural Studies on Xylans from Tension, Opposite and Side Woods of Japanese Beech (Fagus crenata Blume)

Abstract

Structural differences in three 4-0-methyl-glucuronoxylans from tension, opposite and side woods of Japanese beech (Fagus crenata Blume) were investigated. Each 4-0-methyl-glucuronoxylan was isolated from the 1 % potassium hydroxide extract and purified by gel filtration on Sepharose 4B. The weight average molecular weights of three xylans were similar and estimated to be in the range of 20,000-25,000 by gel filtration. A structural analysis by the methylation method and ^<13>C-n.m.r. spectroscopy showed that no substantial differences were detected between these three xylans. ^<13>C-N.m.r. spectroscopy was used in determination of the ring size, anomeric configuration, the position of 0-glycosidation and the purity of these xylans, suggesting the effectiveness of this technique for characterization of polysaccharides in wood.