ISOLATION AND CHARACTERIZATION OF BETA-GALACTOSIDE-SPECIFIC LECTIN FROM KOREAN MISTLETOE (VISCUM-ALBUM VAR. COLORATUM) WITH LACTOSE-BSA-SEPHAROSE 4B AND CHANGES OF LECTIN CONFORMATION

Lectins and its A- and B-chains from Korean mistletoe (Viscum album va r. coloratum) were isolated by affinity chromatography on the Sepharos e 4B modified by lactose-BSA conjugate synthesized by reductive aminat ion of ligand (lactose) to epsilon-amino groups of lysine residues of spacer (BSA) after reduction by NaCNBH3. The lactose-BSA conjugate was coupled to Sepharose 4B activated by cyanogen bromide. The molecular weight determined by SDS-PAGE were a 31 kD of A-chain and a 35kD of B- chain. Amino acid analysis and N-terminal sequencing were performed. T he effects of pH, temperature and guanidine chloride on the conformati on of the lectin were investigated by measuring its intrinsic fluoresc ence and compared with its hemagglutinating activities. Blue shift was detected on the acidic pH and there was a close relationship between activities and conformation of the lectin. Under denaturing conditions , the tryptophan emission profile of lectin showed typical denaturatio nal red shift which also correspond to the conformations and activity of lectin.