PURIFICATION AND CHARACTERIZATION OF LECTIN-II FROM ULEX-EUROPAEUS SEEDS AND AN IMMUNOCHEMICAL STUDY OF ITS COMBINING SITE

The lectin II from Ulex europaeus seeds was purified by adsorption on insoluble polyleucyl hog A + H blood group substance and elution with 35% ethylene glycol, and by chromatography on ε{lunate}-aminocaproyl-fucosyl-amine-agarose. In immunodiffusion against rabbit antiserum to the crude extract, the isolated lectin formed one line which fused with one of the five formed by crude extract. The purified lectin showed two bands on acrylamide electrophoresis under alkaline or acid conditions but only one band of molecular weight 23,000 if the electrophoresis was in the presence of 0.1% sodium dodecyl sulfate at pH 8.8. The agglutinating and precipitating abilities are abolished by EDTA and can be restored by bivalent cations. The purified lectin precipitated to different extents with blood group A1, A2, B, HLeb, Lea, and I precursor substances and with acid- or Smith-degraded substances. Inhibition of precipitation indicated that the lectin site was unusual in that it interacted most strongly with the h-specific oligosaccharide {A figure is presented} and with 2′-fucosyllactose, followed by β1 → 4 linked oligomers of dGlcNAc. Molecular models showed that all these inhibitors have a similarity in three-dimensional structures that could account for their activities. © 1979.