title: Further characterization of the cold agglutinin from the snail Achatina fulica.
abstract: The cold agglutinin from the albumin gland of the snail Achatina fulica was purified to homogeneity by using sheep gastric mucin-Sepharose 4B as affinity column followed by gel filtration on Bio-Gel P-300. The homogeneity was checked by alkaline gel electrophoresis, immunodiffusion and immunoelectrophoresis. The purified cold agglutinin is a glycoprotein of native M2 220,000 consisting of three non-covalently bound subunits of Mr 84,000, 74,000 and 62,000 and having a pI value of 4.5. The predominant amino acids are aspartic acid and glutamic acid (or amides) and serine, which account for 39% of the residues. About 3% of the residues are half-cystine. The lectin is a glycoprotein with about 30.7% carbohydrate, the most abundant sugars being galactose, N-acetylgalactosamine and N-acetylglucosamine. Mannose, xylose and fucose are also present. The inhibition of agglutination of human umbilical-cord erythrocytes by the cold agglutinin is specific for methyl beta-D-galactoside and also for glycolipids present on cord erythrocytes. The c.d. data show only negative ellipticity values in the far-u.v. region for the protein at various concentrations and temperatures and also in the presence of the hapten lactose (at different concentrations), indicating the presence of a random-coil conformation in the agglutinin that varies according to temperature.
mesh_terms: D000373:Agglutinins / Q000302:isolation & purification* / Q000494:pharmacology; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002241:Carbohydrates / Q000032:analysis / Q000494:pharmacology; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003450:Cryoglobulins; D004589:Electrophoresis, Disc; D006017:Glycolipids / Q000494:pharmacology; D006384:Hemagglutination / Q000187:drug effects; D012908:Snails / Q000276:immunology*
chemical_list: D000373:Agglutinins; D000596:Amino Acids; D002241:Carbohydrates; D003450:Cryoglobulins; D006017:Glycolipids; C029443:cold agglutinins