The purification and characterization of wheat-germ agglutinin.
The purification of wheat-germ agglutinin by precipitation with ammonium sulphate and by chromatography on Sephadex G-75, Sepharose-ovomucoid and CM-cellulose is described. This procedure gave agglutinin preparations which were homogeneous on polyacrylamide gels under a variety of conditions. Purified wheat-germ agglutinin formed colourless solutions and was relatively insoluble at neutral pH; maximum solubility in 1mm-tris-HCl buffer, pH7.4, was approx. 1mg/ml. The agglutinin was a glycoprotein containing a single polypeptide chain with an approximate molecular weight of 23000. The N-terminus of the oxidized agglutinin was cysteic acid and the C-terminus was glycine. The amino acid composition showed that the protein was extremely rich in cysteine and cystine; there were 15-17 free SH groups/mol. The absorption maximum for the protein was at 272nm and the molar extinction coefficient at 280nm was 1.09x10(5) litre.mol(-1).cm(-1). Equilibrium dialysis indicated that there was only one binding site per molecule for N-acetylglucosamine.
D000595:Amino Acid Sequence; D000645:Ammonium Sulfate; D002845:Chromatography; D003545:Cysteine / Q000032:analysis; D003956:Dialysis; D004591:Electrophoresis, Polyacrylamide Gel; D005998:Glycine / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000032:analysis / Q000302:isolation & purification*; D037121:Plant Lectins; D012995:Solubility; D014908:Triticum / Q000032:analysis*
D037102:Lectins; D037121:Plant Lectins; D003545:Cysteine; D000645:Ammonium Sulfate; D005998:Glycine