ERYTHROAGGLUTININ FROM PHASEOLUS-COCCINEUS VAR. ALUBIA - CHEMICAL CHARACTERIZATION, SUGAR SPECIFICITY, AND EFFECT ON BLOOD-COAGULATION FACTORS

Purification of the erythroagglutinin from Phaseolus coccineus var. Al ubia was achieved by affinity chromatography on human alpha(1)-acid gl ycoprotein and by ion exchange chromatography. The lectin is a tetrame ric glycoprotein of 31 kDa/subunit with 8% sugar by weight, which aggl utinates erythrocytes without serological specificity and is devoid of mitogenic activity toward human peripheral lymphocytes. The specifici ty of the erythroagglutinin is directed toward the Gal (beta 1-4) or ( beta 1-3) GlcNAc (beta 1-2) Man(alpha 1-) saccharidic sequence present in bi- or triantennary N-acetyllactosamine-type N-glycopeptides or re lated glycans. Alubia erythroagglutinin inhibits the generation of hum an thrombin, very probably by protecting prothrombin from enzymatic cl eavage.