Isolation and preliminary characterization of a highly pyruvylated galactan sulfate from Codium yezoense (Bryopsidales, Chlorophyta)

A pyruvylated galactan sulfate containing D-galactose, sulfate and pyruvate in a molar ratio of about 4:2:1 was isolated from Codium yezoense by extraction with water followed by anion-exchange chromatography. According to NMR spectral data, the majority of pyruvic acid residues are linked as 5-membered cyclic ketals to O-3 and O-4 of galactose residues, and a smaller part of the pyruvate is located at O-4 and O-6. To our knowledge, this is the second detection of pyruvic acid as a component of green algal polysaccharides, while 5-membered pyruvic acid ketals have never been found so far in any algal polysaccharide.