ISOLATION AND CHARACTERIZATION OF A FORSSMAN ANTIGEN-BINDING LECTIN FROM VELVET BEAN (MUCUNA-DERRINGIANA) SEEDS

A Forssman antigen (GalNAc alpha 1-3GalNAc beta 1-3Gal alpha 1-4Gal be ta 1-4Glc beta 1-1Cer)-binding lectin has been purified from velvet be an (Mucuna derringiana) seeds by a combination of affinity chromatogra phy and reversed phase HPLC. This lectin agglutinates both native and trypsin-treated sheep erythrocytes as well as trypsinized rabbit eryth rocytes, but neither native rabbit nor human erythrocytes, irrespectiv e of blood group type. SDS-PAGE and gel filtration chromatography reve al the lectin to be a homodimer consisting of two 54 kDa subunits link ed by non-covalent bonds. The results obtained by quantitative precipi tation, haemagglutination inhibition and TLC overlay assays indicate t hat the Mucuna lectin specifically recognizes Forssman antigen and For ssman disaccharide (GalNAc alpha 1-3GalNAc)-related structures.