Purification And Characterization Of A Lectin From The Edible Mushroom Pleurotus Citrinopileatus

A novel lectin from fresh fruiting bodies of the edible mushroom Pleurotus citrinopileatus was purified and characterized. The purification procedure consisted of extracting soluble proteins in 25mM NaAc buffer, pH4.4, followed by ion exchange chromatography on CM-Sepharose, Q-Sepharose and gel filtration. The purified Pleurotus citrinopileatus lectin (PCL) showed a single protein band with an apparent molecular weight of 17.5 kDa when submitted to SDS-polyacrylamide gel electrophoresis under reducing and unreducing conditions. Its pI was about 6.2, and no carbohydrate was discerned. PCL can agglutinated human regardless of blood type, and rabbit erythrocytes. The hemagglutinating activity of the lectin remains stable after exposure to 50℃ for 30min and in the pH range of 4.0-12.0. All divalent and trivalent metallic chlorides tested did not affect the hemagglutinating activity of the lectin, which indicated that its activity was independent of these metal cations. Hemagglutination inhibition assay suggested that its activity could not be inhibited by any of the mono- and disaccharides tested sugars, but sialic acid and ovomucoid showed strong inhibition at the concentration of 0.39mM and 1.25μg/ml, respectively. Effects of different concentration of GuHCl, urea and SDS on the hemagglutinating activity indicated the activity lost gradually corresponding to the addition of concentration of denaturant. Modification of Trp residues in the absence or presence of 8M Urea resulted in the...