STRUCTURAL INVESTIGATIONS OF THE GALACTAN OF THE SNAIL LYMNAEA STAGNALIS

Article abstract of DOI:10.1016/S0008-6215(00)90430-0

A galactan, isolated from the spawn of the snail Lymnaea stagnalis, contained D-galactose and 0.9percent of nitrogen, but neither L-galactose nor phosphate groups.The <α>_D²⁰ values of the galactan and its first Smith-degradation product were +19.5 deg and +20 deg, respectively.During each of two consecutive Smith-degradations of the galactan, 1 mol of periodate was consumed and 0.45 mol of formic acid was liberated per mol of "anhydrogalactose" unit.Methylation analyses of the galactan and its first Smith-degradation product yielded equal proportions of 2,3,4,6-tetra-O-methyl- and 2,4-di-O-methyl-galactose.Only small quantities of 2,4,6- 4.9 molpercent) and 2,3,4-tri-O-methylgalactose (0.7 molpercent) were formed from the galactan, whereas the first Smith-degraded product gave 15.6 and 20.4 molpercent, respectively.The product of the second Smith-degradation disintegrated and the following oligosaccharides were identified: β-D-Gal-(1-1)-L-Gro, β-D-Gal-(1-3)-β-D-Gal-(1-1)-L-Gro, β-D-Gal-(1-6)-β-D-Gal-(1-1)-L-Gro, β-D-Gal-(1-6)-D-Gal-β-D-Gal-(1-3)-β-D-Gal-(1-1)-L-Gro, β-D-Gal-(1-3)-<β-D-Gal-(1-6)>-β-D-Gal-(1-1)-L-Gro, β-D-Gal-(1-3)-β-D-Gal-(1-3)-β-D-Gal-(1-6)-β-D-Gal-(1-1)-L-Gro, and β-D-Gal-(1-3)-β-D-Gal-(1-3)-β-D-Gal-(1-1)-L-Gro.Thus, the galactan is highly branched with the backbone containing sequences of either exclusively (1-6)-linked or of more or less regularly alterneting (1-3)- and (1-6)-linked units.The side chains vary in length and in the degree of branching.In immunoprecipitin studies, a high degree of species-specificity was seen when various snail galactans were tested with the antiserum to the Lymnaea stagnalis galactan.