Partial Purification and Characterization of Lectin from the Seeds of Cissus poplunea

Abstract

Lectin is a glycoprotein substance, usually of plant origin, of non-immunoglobulin nature and capable of binding to carbohydrate moieties of complex glycoconjugates. This underlies its clinical significance. Hence, purification steps comprising of centrifugation, salting-out, ultra filtration, dialysis and anion exchange affinity chromatography were used to purify the protein from the seed of Cissus populnea. The purified lectin agglutinated non-specifically red blood cells of human type A, B and O. The hemagglutinating activity of the lectin towards human erythrocytes was inhibited by D-fructose, D-glucose and CuSO4. However the lectin activity was enhanced by D-galactose and MgCl2. Stability studies showed the purified protein to be stable at a spectrum of 20-40°C and at pH range of 6-8 and 10-11. The kinetic study on the purified protein indicated 26271HU and 278.2 L for Vmax and Km, respectively. However, result from paper chromatography on the carbohydrate isolate during purification indicated presence of a ketone sugar having same appearance with fructose standard, a sugar clinically established as the major source of energy during spermatogenesis. It was observed that heamagglutinating activity of the lectin from Cissus populnea towards human erythrocytes was non-selective to type of blood groups. It could be stated that Cissus populnea consumption may pose no threat to patient with challenge in metabolising glucose, since its main carbohydrate content is fructose.