STRUCTURE OF AN ARABOGALACTAN FROM TAMARACK (LARIX LARICINA)

Abstract

A water-soluble polysaccharide containing L-arabinose and D-galactose in a molar ratio 1:3.8 was isolated from tamarack. Fractionation with ethanol from aqueous solution yielded one main component which was judged to be homogeneous on the basis of electrophoresis and sedimentation data. Hydrolysis of the fully methylated polysaccharide yielded, 2,3,5-tri-O-methyl-L-arabinose (2 moles); 2,3,4,6-tetra-O-methyl-D-galactose (16 moles); 2,5-di-O-methyl-L-arabinose (5 moles); 2,3,4-tri-O-methyl-L-arabinose (5.5 moles); 2,3,4-tri-O-methyl-D-galactose (11 moles); 2,4,6-tri-O-methyl-D-galactose (3 moles); 2,6-di-O-methyl-D-galactose (1 mole); 2,4-di-O-methyl-D-galactose (20 moles); 2-O-methyl-D-galactose (3 moles).Possible structures for the arabogalactan are proposed and discussed on the basis of these results.