Cruz, A.K.M.^1*; Albuquerque, E.M.M.¹; Evangelista, I.W.V¹; Santos, V.O¹; Brito, A.S¹; Vasconcelos, C.L.²; Torri, G.³; Chavante,S.F¹;  Sales, M.P.¹ and Oliveira, F.W.¹.

A acidic galactan (AG) has been purified partially of the mollusc Pomacea sp eggs. This polysaccharide appears during the embryonic development around the 7^th day and progressively decrease until the 12^th day with the appearance of chondroitin sulfate. The objective of this study was to investigate the acidic galactan structure using definitive methods of structural carbohydrate analysis. The polysaccharides were extracted by proteolysis (maxatase), trichloroacetic acid and precipitation with ethanol. The AG obtained was isolated by acetone precipitation. The characterization was realized by chemical methods such as pyruvic acid determination, hexosamines, gel filtration chromatography, chromatography in paper, relative viscosity, and ¹H and ¹³C NMR spectroscopy. The acidic galactan molecular weight is approximately 25 x 10⁵ Da, and the amount of pyruvic acid present is approximately 1 mol/100mol of galactose in the molecule. The hexosamine present is 6,14% and D-galactose 86%. Regarding to the relative viscosity the value was 1.74±0.07dL^-1.g. The ¹³C NMR establishes the structure of the AG to be even more complex than previously determined containing anomer carbons at about 106.1ppm and 107 ppm. The signals at 71.70, 75.48, 73.48 and 77.80 ppm, are from C-2, C-3, C-4 and C-5, respectively. 3-O-substituted pyruvic acid acetal units (177.6, 101.1, 26.2 ppm) and hexosamine residues represented by H-1 of the galactosamine that was found in 4.67ppm and H-2 at 3.19ppm. These results have a particular interest since they revealed important informations about structure of the AG that can be used as a bioactive polymer.

Supported by: CAPES and CNPq.