Abstract

The partial purification and characterization of hemagglutinin ( lectin ) was carried out from the hemolymph of adult American cockroach, Periplaneta americana. The hemolymph was drawn from cockroach and lectin was purified by single-step method, using ammonium sulphate (NH4)2SO4 salt fractionation and gel filtration. Gel filtration showed two peaks. The hemagglutination assay (HA) was observed in the 20th fraction of the second peak. The purified lectin showed a molecular weight of 26.8kDa on SDS-PAGE. The purified lectin showed an increase in HA at pH 7.5, thereafter, a sharp decline at pH 8. This indicates that HA was specific to a certain pH. Similarly, an increase in HA was observed till 30C, followed by a decline at 40C. This suggests the heat-labile nature of lectin. The HA showed the highest specificity to divalent Ca2+, and showed no specificity for Ba2+ . The HA, showed the highest inhibition for sugar D- galactose and a least inhibition for D-lactose. The assay for HA to different vertebrate blood group showed a highest activity to goat RBCs. The study concludes that carbohydrate-binding specific lectin is important for recognition of the cell surface carbohydrate of invading pathogens.

Key words: Purification, Lectin, Sugar specificity, pH, Temperature, Periplaneta americana