EFFECTS OF THE DEGREE OF POLYMERIZATION ON THE BINDING OF XYLOGLUCANSTO CELLULOSE

Xyloglucan oligosaccharides were isolated with various degrees of poly merization (DP) and reduced with tritiated sodium borohydride. The H-3 -oligosaccharides were tested for their ability to bind to amorphous a nd microcrystalline celluloses and to cellulose filter paper. The time course of binding indicated that the radiolabeled oligosaccharides co ntinued to be bound for at least 1 h after heating at 120 degrees C. T he binding probably required the organization of the oligosaccharides and celluloses by gradual annealing after heating. Although neither pe ntasaccharide (glucose: xylose, 3:2), heptasaccharide (glucose:xylose, 4:3) and nonasaccharide (glucose:xylose: galactose:fucose, 4:3:1 : 1) failed to bind to the celluloses, binding occurred with oligosacchari des with DP equivalent to more than four consecutive 1,4-beta-glucosyl residues. The extent of binding to the celluloses increased gradually from octasaccharide (glucose:xylose, 5:3) to hendecosanosaccharide (g lucose/xylose, 12:9), with the increase in the DP of 1,4-beta-glucosyl residues. The binding of reduced cello-dextrins to cellulose required at least 4 consecutive 1,4-beta-glucosyl residues. The extent of bind ing of cellopentitol or cellohexitol to cellulose was similar to that of hendecosanosaccharide, showing lower binding for xyloglucan oligosa ccharides in spite of longer chains of 1,4-beta-glucosyl residues. The se findings suggest that the mode of binding to cellulose of xylogluca n oligosaccharides is different from that of cello-oligosaccharides.