Formolysis studies on some polysaccharides from red seaweeds

Abstract

Formolysis of the permethylated agaroses from marine algae of the Pterocladia species and Gracilaria secundata, and of the permethylated porphyran from Porphyra columbina, resulted in a much higher recovery of 3,6-anhydro-2-O-methyl-L-galactosyl (relative to methylated D-galactosyl) derivatives than was obtained from conventional methylation analyses. The formolysis method, when followed by sulfuric acid hydrolyses, provided a novel method for the estimation of 3,6-anhydro-L-galactose residues in these agar-type polysaccharides. The 3,6-anhydro-2-O-methyl-L-galactose was determined by gas chromatography of its alditol acetate, and identified by g.l.c./m.s.