Rhamnan sulfate from cell walls of Monostroma latissimum

Rhamnan sulfate from cell walls of Monostroma latissimum was purified through subsequent chromatographic systems. The purified polysaccharide consisted of large amounts of rhamnose residues and appeared to be an entire homopolysaccharide. Antithrombin activity was lower than rhamnan sulfate previously obtained from M. nitidum but similar to standard heparin. Studies of the major structural parts of the rhamnan sulfate by periodate oxidation, Smith degradation and permethylation, showed it to consist of 1,3- and 1,2 linked rhamnose residues in a ratio of 3:2. Sulfate was mainly substituted at C-3 or C-4 in the 1,2-linked rhamnose residue. The detection of oligosaccharides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry supports this structure. These results suggested that rhamnan sulfate from the Monostromaceae has quite different structural properties from ulvan from the Ulvaceae. (C) 1998 Elsevier Science Ltd. All rights reserved.