title: Anti-galactan activity in Tridacna maxima (Röding) haemolymph. Calcium dependence of the haemagglutinins and precipitins.
abstract: A powerful natural agglutinin with haemagglutinating and precipitating properties has been found in the haemolymph from the elongate clam Tridacna maxima (Röding). The agglutinin shows anti-galactan properties and reacts with a variety of bacteria-, plant-, invertebrate- and vertebrate-derived galactans, glycopeptides and polysaccharides. Previous studies which showed that the agglutinin-combining sites were inhibited by 2-acetamido-2-deoxy-D-galactose and D-galactose also revealed some anomalies in the reactions of the agglutinin with different saccharide-containing macromolecules. In an attempt to resolve these anomalies, the present study further examines the precipitating and haemagglutinating properties of the agglutinin and illustrates a requirement of the agglutinin for Ca2+. The ability of the T. maxima agglutinin to precipitate with structures containing terminal beta-linked 2-acetamido-2-deoxy-D-galactopyranosyl or D-galactopyranosyl groups suggests that the Tridacna haemolymph and purified lectin will find considerable application in the study of many biologically important carbohydrates.
mesh_terms: D000017:ABO Blood-Group System; D000373:Agglutinins / Q000032:analysis*; D000818:Animals; D049872:Bivalvia / Q000276:immunology*; D002118:Calcium / Q000494:pharmacology*; D004912:Erythrocytes / Q000276:immunology; D006384:Hemagglutination / Q000187:drug effects; D006385:Hemagglutination Inhibition Tests; D006388:Hemagglutinins / Q000032:analysis*; D006458:Hemolymph / Q000276:immunology*; D006801:Humans; D011134:Polysaccharides / Q000276:immunology*; D011233:Precipitin Tests; D011234:Precipitins / Q000032:analysis*
chemical_list: D000017:ABO Blood-Group System; D000373:Agglutinins; D006388:Hemagglutinins; D011134:Polysaccharides; D011234:Precipitins; D002118:Calcium