PURIFICATION AND PROPERTIES OF 4 MONOCOT LECTINS FROM THE FAMILY ARACEAE

Four new monocot lectins from the tubers of araceous plants, namely, A risaema consanguineum Schott (ACA), A. curvatum Kunth (ACmA) and Sauro matum guttatum Schott (SGA) from the tribe Areae, and Gonatanthus pumi lus D. Don (GPA) from the tribe Colocasieae have been purified by affi nity chromatography on asialofetuin-linked amino activated silica bead s. These lectins possess similar physicochemical and biological proper ties. All the lectins gave a single peak on HPLC size exclusion and ca tion exchange columns, and a single band on PAGE, (pH 4.5). In SDS-PAG E, all the lectins gave a single band corresponding to a subunit of M( r) 13 000. All the lectins yielded multiple peaks on anion-exchange co lumn, multiple bands on non-denatured PAGE (pH 8.3) and a family of ba nds on isoelectric focusing. The lectins agglutinate rabbit, rat and s heep red blood cells (RBCs) but are inactive towards human ABO erythro cytes. The haemagglutination activity of these lectins is inhibited by asialofetuin only, while simple sugars/derivatives including chitin, porcine mucin and fetuin did not react. In serological studies against rabbit anti-SGA serum, all four lectins produced immunoprecipitin lin es. The lectins within each tribe were identical but the lectins belon ging to the tribe Areae were only partially identical to the lectins f rom the tribe Colocasieae.