Isolation and characterisation of a fourth hemagglutinin from the red alga, Gracilaria verrucosa, from Japan

Isolation and characterisation of marine algal hemagglutinins or lectins ar e essential for their potential industrial application as specific carbohyd rate affinity ligands. The phosphate buffer extract of the red alga, Gracil aria verrucosa (Huds.) Papenfuss (Gigartinales, Rhodophyta) from Japan is k nown to contain three different hemagglutinins. The extract of the alga col lected in March 1993 from Kagawa Prefecture, Japan, was purified by ammoniu m sulphate fractionation, ion exchange and gel filtration chromatography. U sing gel filtration, two peaks were obtained (hereafter Peak 1 and Peak 2) which differed in molecular size and hemagglutinating activity against hors e erythrocytes. Peak 1 corresponded to the known high molecular weight hema gglutinin, H-GVH. Peak 2 contained large amounts of hexose and sulphate alo ng with a small amount of protein. It had a low molecular weight (gel filtr ation) similar to that of two of the previously reported G.verrucosa hemagg lutinins but differed in its electrophoretic behaviour. Peak 2 is therefore a fourth hemagglutinin. Its activity was not inhibited by any of the monos accharides tested but by the complex glycoproteins such as asialofetuin and fetuin. It had no divalent cation requirement for hemagglutination. The pr operties of this novel hemagglutinin could prove useful in industrial appli cations.