Galactose methylation analyses

A methylation analysis of S14, performed in the authors laboratory,44 gave 2,3,4,6-tetra-O-methyl-D-galactose, 2,4,6-tri-O-methyl-D-galactose, and 2,3,6-tri-O-methyl-D-glucose in the proportions 1 1 1. Although these are the same components as previously reported, the proportions are different. In addition to these sugars, 2-deoxy-3-0-methyl-2-(methylamino)-D-glucose was also obtained. 

Similarly, methylation analysis of a partially hydrolyzed sample of the Klebsiella type 38 capsular polysaccharide, composed of pentasaccharide repeating units (5), revealed that the terminal 3-deoxy-L-g/ycero-pentulosylonic acid group (6) was located at 0-3 of a D-galac-tosyl residue (7), as the 6-O-methyl-D-galactose in the methylation... 

Those galactans that have been studied (see the preceding) have degrees of polymerization ranging from 33 in white willow161 to 50 in sycamore-cell primary-walls.183 These values were obtained by vapor pressure and osmosis studies,161 and by comparing the ratio of terminal to intrachain galactose units by methylation analysis.163... 

The xyloglucan from cell walls of Phaseolus coccineus39 contained l-arabinose, L-fucose, D-galactose, D-xylose, and D-glucose in the ratios of 4 6 9 34 46. Treatment with a-L-fucosidase released 85% of the l-fucose, and this fact, together with the results of methylation analysis, showed that L-fucose was present solely as terminal, a-linked groups. 

Recently, Laidlaw and Wylam reported27 the complete methylation analysis of stachyose (see the following Section). Their results, likewise, require a 1,6 linkage between the D-glucose and D-galactose units. 

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