Structural Studies on Spisulan: A Mucopolysaccharide from Clams

Spisulan, a novel type of acid mucopolysaccharide, has been isolated from clam tissues in purified form by relatively mild extraction procedures. The mucopolysaccharide is unusual in having a backbone peptide consisting of poly- threonine repeating units believed to be joined together by proline to form chains of relatively large size, as judged by viscosity and gel filtration results from Sephadex G-200. Chemical evidence indicates that short carbohydrate branches containing N-acetyl galactosamine, galactose and fucose are attached to the backbone peptide structure, presumably by glycosidic linkage to threonine. The sulfate content is sufficient to account for monosulfation of all carbohydrate groups and results from periodate oxidation are in agreement with this.