Isolement et propriétés d'une phytohémagglutinine anti A1 extraite des graines de dolichos biflorus

Abstract A phytohaemagglutinin from Dolichos biflorus seeds was purified by fractional precipitation with ammonium sulphate, gel filtration and CM-cellulose chromatography. This agglutinin was homogeneous according to starch gel, polyacrylamide gel electrophoresis and ultracentrifugation. The agglutinating activity involves A 1 erythrocytes almost exclusively. This agglutinin shows no mitotic activity. It is an acid glycoprotein (pH 1 5.5 with a sedimentation coefficient of s ° 20, w = 6.3 S . The carbohydrate content is 3.75% with 2.5% of neutral sugars (essentially mannose with few xylose, fucose, arabinose and glucose). Glucosamine is the only hexosamine present. No sialic acid could be identified. The amino acid composition shows a high content of diacids and hydroxyamino acids, almost no sulfur amino acids and a substantial amount of aromatic amino acids ( E 1 cm 1% = 11.3). Erythroagglutinating activity is not impaired by proteolysis carried out on the native agglutinin. Proteolysis of heated agglutinin completely destroys the biological activity. The last same effect is shown by periodate oxidation.