On the Steric Configuration of the Urushi Polysaccharide

This paper presents the steric configuration of a polysaccharide obtained from the latex of the Japanese lacquer tree. Thus, the polysaccharide consisted of galactose and galacturonic acid, and the main chain of polysaccharide was proved to be linked with 1 → 3 linkage of galactose residue of 6-O-galacturonosyl galactose unit by the periodate oxidation method. The molecular weight was calculated to be 6 × 104 by Archibald’s ultracentrifugal method. The configuration of the polysaccharide was discussed to be α helical structure of which one turn of the helices consists of 6 to 7 6-O-galacturonosyl galactose units and the diameter of the helix is 21 A and one pitch is 9.5 A on the basis of viscosity measurements, color reaction with iodine, crystallization with capronic acid and consideration of molecular models.