FUNORAN FROM THE RED SEAWEED, GLOIOPELTIS-COMPLANATA - POLYSACCHARIDES WITH SULFATED AGAROSE STRUCTURE AND THEIR PRECURSOR STRUCTURE

Funoran extracted from the red seaweed, Gloiopeltis complanata, was fr actionated based on the solubility of its cetylpyridinium salt in KCl solution to give the fractions PS1 and PS2. PS2 was further fractionat ed into PS2G that formed a gel in 0.5 N KCl, and PS2S that did not for m a gel in saturated KCl. PS1, PS2G and PS2S were different in composi tion and properties showing that the funoran was heterogeneous. On the basis of the results from composition analyses, partial methanolysis studies, methylation studies, C-13-NMR spectrum measurements, and regi oselective desulphation studies employing a silylating reagent, N,O-bi s(trimethylsilyl)acetamide, PS2G was shown to consist chiefly of 6-O-s ulphated agarose, repeats of SO3-beta-D-Gal(1-->4)3,6-anhydro-alpha-L- Gal(1-->; and PS2S to contain repeats of -->3)6-SO3-beta-D-Gal(1-->4)6 -SO3-alpha-L-Gal(1--> as well as smaller amounts of -->3)2,6-di-SO3-be ta-D-Gal(1--> and -->3)2-SO3-beta-D-Gal(1--> residues.