牛血清白蛋白与锌试剂作用机理的荧光法研究

Mechanism Studies on the Combination Reaction between Bovine Serum Albumin and Zincon by Fluorescence Spectra

采用荧光光谱法、紫外-可见光度法研究了牛血清白蛋白(BSA)与锌试剂(ZCN)作用的机理。牛血清白蛋白(BSA)在280nm的光激发下能发射345nm的荧光(即λex=280nm,λem=345nm)。当BSA中加入适量的锌试剂(ZCN),BSA的荧光被部分猝灭。由Stern-Volmer方程和双倒数曲线Lineweaver-Burk方程获得了反应的动态猝灭常数、静态猝灭常数,并对猝灭的类型做出了推断。通过计算反应的热力学参数讨论了结合反应的主要作用力类型。根据Frster非辐射能量转移机理,计算了给体(BSA)与受体(ZCN)间距离r=5.07nm和能量转移效率E=0.67。证实了该体系的荧光猝灭是通过能量转移机制产生的单一静态猝灭过程。

The characteristics of binding reaction between bovine serum albumin （BSA） and zincon （ZCN） were studied by fluorescence spectra and ultraviolet-visible absorption spectra, The bovine serum albumin can emit fluorescence （λem = 345 rim） under irradiation of ultraviolet light （λex=280 nm）. After the zincon （ZCN） was added into BSA solution the fluorescence of BSA was quenched partially. The results indicated that ZCN was strongly bound to BSA. According to Stern-Volmer equation and Lineweaver-Burk equation, the quenching constant and the thermodynamic parameters were obtained. From the thermodynamic parameters the binding power between ZCN and BSA can be judged. The binding distance（r= 5.07 nm） and energy transfer efficiency（E=0. 67） between donor （BSA） and acceptor （ZCN） were obtained by Foerster＇s non-radiative energy transfer mechanism. It is confirmed that the combination reaction between ZCN and BSA is a single static quenching process, and their interaction may be interpreted with energy transfer mechanism.