荧光光谱法研究丙烯酰胺与牛血清白蛋白的相互作用

Interaction between acrylamide and bovine serum albumin by fluorescence spectroscopy

运用荧光光谱法研究了致癌物质丙烯酰胺与牛血清白蛋白(BSA)的相互作用。实验指出丙烯酰胺对BSA有荧光猝灭作用,通过对荧光光谱数据进行计算可求得丙烯酰胺与BSA在298,302和306K3个温度下相互作用的Stern-Volmer常数,并判断其猝灭类型为静态猝灭。利用双对数方程求出两者的结合常数为1.13×106 L.mol-1,结合位点数为1。通过分析作用过程的热力学参数可知丙烯酰胺与BSA之间的作用以疏水作用力和静电引力为主。文中采用同步荧光光谱法研究了丙烯酰胺对BSA构象的影响,进而利用位点竞争实验确定了丙烯酰胺主要结合在BSA的位点一上(site I)。还研究了几种人体内常见的金属离子对丙烯酰胺和BSA相互作用的影响,发现这些金属离子都不同程度减弱了丙烯酰胺与BSA的结合能力。

The interaction between acrylamide and bovine serum albumin （BSA） was studied by fluorescence spectroscopy. It was found that the fluorescence quenching of the interaction was due to the static quench-ing. The molecular quenching constants （Kq） ,the binding constants （KA） and the binding sites at 298,302 and 306 K were calculated, respectively. Furthermore, thermodynamic parameters evaluated from Van＇ t Hoff equation suggest that the interaction was spontaneous and mainly by an initial hydrophobic associa-tion and electrostatic interaction. The effect of acrylamide on the conformation of BSA was investigated by synchronous fluorescence. The competitive experiments with the use of site markers indicated that the binding of acrylamide with BSA is primarily in site I. It was also shown that the binding constants were af-fected by the metal ions.