A STUDY OF LECTIN FROM SMILAX LAUCEAEFOLA ROXB VAR.OPACA A.DC BY FLUORESCENCE SPECTROSCOPY
白茯苓凝集素的荧光光谱研究

Tryptophan (Trp) residues of lectin from Smilax lauceafolia Roxb Var. opaca A. DC(SLL) were determined with p-dimethyiamino (DBA). The result showed thatthere were 4 Trp residues in SLL. They were an on the surface of SLL, as demonstrated bychemical modification with N-Bromosuccinimide (NBS). The fluorescence spectra of SLL excited at 280nm and 295nm showed a maximum at 335nm. Change of temperature didn't obviously affect the fluorescence emission spectra. The fluorescence intensity of SLL modified byNBS decreased with an excitation wavelength of 295mp and the emission peak had ablue-shift of 7nm. SLL modified by NBS lost the agglutination activity. These resuits impliedthat conformation of SLL modaified by NBS was changed. The Trp residue fluorescence ofSLL was not quenched by KI, but 50% and 100%was quenched by CsCl and acrylamiderespectively. We deduced that the Trp residues of SLL were located in the hydrophobic pocketof the glycoprotein surface.