OCCURRENCE OF β-D-GALACTOPYRANOSYL UNITS ESTERIFIED AT O-6 WITH 2-AMINOETHYLPHOSPHONIC ACID IN THE D-GALACTAN OF ALBUMEN GLANDS OF THE SNAIL MEGALOBULIMUS PARANAGUENSIS

Article abstract of DOI:10.1016/S0008-6215(00)90706-7

The albumen glands of the snail Megalobulimus paranaguensis were previously found to contain a branched β-D-galactopyranan consisting mainly of nonreducing end-groups and 3,6-di-O-substituted residues with smaller proportions of 3-O- and 6-O-substituted units. (13)C-n.m.r. spectroscopy has now shown that 2-aminoethylphosphonic acid (1) is an additional component and its presence was confirmed by cellulose-plate chromatography.Furthermore, the 2-aminoethyl-phosphonic acid-substituted oligosaccharides, formed on partial hydrolysis of the polysaccharide, were isolated, examined by fast-atom-bombardment mass spectrometry, and found to have molecular weights consistent with monophosphonic esters of 1.The (13)C-n.m.r. spectrum of this mixture indicated substitution of D-galactopyranosyl units at O-6 with esters of 1, and this was confirmed by spectral examination of a monosubstituted D-galactose isolated after strong acid hydrolysis of the polymer.The snail D-galactan contained one ester of 1 every 34 residues, it was free of other components such as protein, lipid, and nucleic acid, and is the first polysaccharide of this type has been identified.