title: Purification and characterization of four isolectins of mushroom (Agaricus bisporus).
abstract: Four lectins were purified from a mushroom (Agaricus bisporus) by ammonium sulfate fractionation, anion-exchange chromatography, affinity chromatography on bovine submaxillary mucin-Sepharose 4B and preparative isoelectric focusing. They were designated as ABA-I (pI 6.70), II (pI 5.98), III (pI 5.69) and IV (pI 5.53). Polyacrylamide gel electrophoresis of each lectin in the presence of sodium dodecyl sulfate gave a single band with an apparent molecular mass of 16 000 Da. Sedimentation equilibrium analysis suggested that each lectin is a tetramer of subunits. The four lectins were found to have quite similar carbohydrate-binding specificities. The hemagglutination activities of the lectins were effectively inhibited by bovine and porcine submaxillary mucins (BSM and PSM), and NH2-terminal glyco-octapeptides obtained by cyanogen bromide cleavage of human erythrocyte glycophorin A. In addition, desialylated PSM-glycopeptides were more potent inhibitors than untreated PSM-glycopeptides. Among monosaccharides and their glycosides, only methyl N-acetyl-alpha-galactosaminide inhibited lectin binding at a high concentration, but a synthetic oligosaccharide, O-beta-galactopyranosyl-(1----3)-O-(2-acetamido-2-deoxy-alpha-D- galactopyranosyl)-N-tosyl-L-serine, was a strong inhibitor.
mesh_terms: D000363:Agaricales / Q000032:analysis*; D000373:Agglutinins / Q000302:isolation & purification; D000596:Amino Acids / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D006020:Glycopeptides / Q000032:analysis; D006021:Glycophorins / Q000378:metabolism; D006385:Hemagglutination Inhibition Tests; D006386:Hemagglutination Tests; D006801:Humans; D066298:In Vitro Techniques; D007525:Isoelectric Focusing; D037102:Lectins / Q000302:isolation & purification* / Q000494:pharmacology; D008970:Molecular Weight; D010047:Ovalbumin / Q000032:analysis; D014168:Transferrin / Q000032:analysis
chemical_list: D000373:Agglutinins; D000596:Amino Acids; D002241:Carbohydrates; D006020:Glycopeptides; D006021:Glycophorins; D037102:Lectins; D014168:Transferrin; D010047:Ovalbumin