Structural diversity among sulfated alpha-L-galactans from ascidians (tunicates). Studies on the species Ciona intestinalis and Herdmania monus.

Sulfated polysaccharides occurring in the tunic of different species of ascidians differ markedly in electrophoretic pattern and chemical composition. A purified sulfated alpha-L-galactan from Herdmania monus was studied using methylation analysis and NMR spectroscopy; it is composed mainly of 3-sulfated 4-linked alpha-L-galactopyranoyl units. This is the first description of a homo-polymer of sulfated alpha-L-galactose. In contrast, the sulfated L-galactan from Ciona intestinalis shows marked structural heterogeneity and a low sulfate content. These data indicate unusual structural diversity among sulfated L-galactans from different species of ascidians.