STRUCTURE AND ANTICOAGULANT ACTIVITY OF A FUCOSYLATED CHONDROITIN SULFATE FROM ECHINODERM - SULFATED FUCOSE BRANCHES ON THE POLYSACCHARIDE ACCOUNT FOR ITS HIGH ANTICOAGULANT ACTION

A polysaccharide isolated from the body wall of the sea cucumber Ludwi gothurea grisea has a backbone like that of mammalian chondroitin sulf ate: [4-beta-D-GlcA-1-->3-beta-D-GalNAc-1](n) but substituted at the 3 -position of the beta-D-glucuronic acid residues with sulfated alpha-L -fucopyranosyl branches (Vieira, R. P., Mulloy, B., and Mourao, P. A. S. (1991) J. Biol. Chem. 266, 13530-13536). Mild acid hydrolysis remov es the sulfated alpha-L-fucose branches, and cleaved residues have bee n characterized by H-1 NMR spectroscopy; the most abundant species is fucose 4-O-monosulfate, but 2,4- and 3,4-di-O-sulfated residues are al so present. Degradation of the remaining polysaccharide with chondroit in ABC lyase shows that the sulfated alpha-L-fucose residues released by mild acid hydrolysis are concentrated toward the non-reducing end o f the polysaccharide chains; enzyme-resistant polysaccharide material includes the reducing terminal and carries acid resistant L-fucose sub stitution. The sulfated alpha-L-fucose branches confer anticoagulant a ctivity on the polysaccharide. The specific activity of fucosylated ch ondroitin sulfate in the activated partial thromboplastin time assay i s greater than that of a linear homopolymeric alpha-L-fucan with about the same level of sulfation; this activity is lost on defucosylation or desulfation but not on carboxyl-reduction of the polymer. Assays wi th purified reagents show that the fucosylated chondroitin sulfate can potentiate the thrombin inhibition activity of both antithrombin and heparin cofactor II.