Acidic heteropolysaccharide AM-2

Acidic heteropolysaccharide AM-2 having the following physiochemical characteristics:

• (1) composition
• composed of glucose, rhamnose, mannose, glucuronic acid and acetyl group as main components, the molar ratio of glucose:rhamnose:mannose:glucuronic acid being 4:0.9.about.1.1:0.9.about.1.1:0.9.about.1.1 and the acetyl group content is 4 to 8%;
• (2) infrared spectrum
• the infrared spectrum is as shown in FIG. 1;
• (3) color reaction
• Anthrone reaction:
• positive
• Carbazole reaction:
• positive
• Elson-Morgan's reaction:
• negative
• Iodine reaction:
• positive;
• (4) solubility in solvents
• soluble in water, and insoluble in ethanol, ether, acetone;
• (5) color and appearance
• the purified polysaccharide is white, cottony or fibrous;
• (6) viscosity
• the aqueous solution is colorless, transparent and viscous, and the viscosity of 1% solution is 1200 to 2000 cps as determined with a torque measuring viscometer at 25.degree. C. and a rate of 30 rpm;
• (7) elemental analysis:
• C:
• 39.9.+-.1%;
• H:
• 6.2.+-.1%;
• N:
• 0%;
• ash:
• 3.0.+-.1.0%;
• (8) Specific rotation
• [.alpha]sub.D.sup.27 =0.about.+20
• (C=0.33 in the aqueous solution);
• (9) molecular weight
• about 10.sup.5 or above;
• (10) melting point
• the polysaccharide turns dark brown at 190.degree. C. and decomposes at 250.degree. C.;
• and
• (11) nuclear magnetic resonance spectrum
• the .sup.13 C-nuclear magnetic resonance spectrum is as shown in FIG. 7.