STRUCTURE OF AN ARABINOGALACTAN FROM TAMARACK (LARIX LARICINA)

Partial acid hydrolysis of an arabinogalactan from tamarack wood yielded:(I) L-arabinose,(II) D-galactose,(III) 3-O-β-L-arabinopyranosyl-L-arabinose,(IV) 6-O-β-D-galactopyranosyl-D-galactose,(V) 3-O-β-D-galactopyranosyl-D-galactose,(VI) O-D-galactopyranosyl(1 → 6)-O-D-galactopyranosyl(1 → 6)-D-galactose,(VII) 3,6-di-O-(galactopyranosyl)-D-galactopyranose,(VIII) O-D-galactopyranosyl(1 → 3)-O-D-galactopyranosyl(1 → 3)-D-galactose,(IX) O-D-galactopyranosyl(1 → 6)-O-D-galactopyranosyl(1 → 3)-D-galactose,(X) O-D-galactopyranosyl(1 → 6)-O-D-galactopyranosyl(1 → 6)-O-D-galactopyranosyl(1 → 3)-D-galactose,(XI) O-D-galactopyranosyl(1 → 6)-O-D-galactopyranosyl(1 → 3)-O-D-galactopyranosyl(1 → 3)-D-galactose.A previously published structure for the tamarack polysaccharide was revised to show that not more than two consecutive 1 → 3 or 1 → 6 linkages respectively were present in the main core of the repeating unit. Some of the 6-O-β-D-galactopyranosyl-D-galactose units occurred as side chains as well as in the main body of the molecule.