Structural elucidation of an acidic galactan from the eggs of mollusc Pomacea lineata

A polysaccharide fraction containing acidic galactan (AG) was obtained from eggs of the mollusc Pomacea lineata by precipitation with acetone. Its structure was investigated using a combination of chemical analysis, intrinsic viscosity and NMR spectroscopy methods, including 1D and 2D, COSY, TOCSY and HSQC experiments. The chemistry analysis showed that the acidic galactan did not possess neither sulfate nor uronic acid. The intrinsic and relative viscosities were 0.44 ± 0.05 and 1.744 ± 0.07 dL.g−1, respectively. The NMR confirmed that the acidic galactan had a backbone containing β-d-Gal is a predominant compound and presence of the β-d-GlcNAc in less proportion. In addition, were found pyruvate groups forming six-membered cyclic ketals as 4,6-O-(1′carboxy)-ethylidene-β-d-galactose residues with configuration R in some β-d-Galp.