Structural diversity among sulfated α‐L‐galactans from ascidians (tunicates)

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.