荧光法研究7-乙基喜树碱、10-羟基喜树碱和牛血清白蛋白的相互作用

Interaction Between Bovine Serum Albumins and 7-Ethylcamptothecin or 10-Hydroxycamptothecin

采用荧光光谱法、分光光度法研究7-乙基喜树碱(7-ECPT)和10-羟基喜树碱(10-HCPT)与牛血清白蛋白(BSA)相互结合反应。实验表明,喜树碱类药物与BSA的相互结合作用为单一的静态猝灭过程,在溶液中二者以摩尔比1∶1牢固结合,其结合反应的平衡常数K0分别为:K0,7-ECPT=3·69×105L·mol-1、K0,10-HCPT=8·00×105L·mol-1。根据F rster非辐射能量转移机理,求算了给体(BSA)与受体(喜树碱类药物)间距离r和能量转移效率E分别为:r7-ECPT=3·03nm、r10-HCPT=3·27nm、E7-ECPT=0·48、E10-HCPT=0·31。并推测了二者之间的主要作用力。

The binding reaction between camptothecin derivatives, such as 7-Ethylcamptothecin （7-ECPT） and 10-hydroxycamptothecin （10-HCPT）, and bovine serum albumins （BSA） were studied by fluorescence and uhraviolet-visible absorption spectrometry. The research results indicate that the combination reaction of them is a single static quenching process, camptothecin derivatives strongly bind BSA with the molar ratio of 1 ： 1, the binding equilibrium constants （K0） are as follows, K0.7·ECPT = 3. 69×10^5 L/mol, K0.10·HCPT = 8.00×10^5 L/mol. The shortest binding distance （r） and energy transfer efficiencies （E） between donor （BSA） and acceptor（camptothecin derivatives） were obtained by Foerster＇s nonradiative energy transfer mechanism, the shortest binding distance （r） and energy transfer efficiencies （E） are as follows, r7·ECPT = 3.03 nm, r10·HCPT = 3.27 nm; E7·ECPT =0.48, E10·HCPT = 0.31. The main sort of binding force between them is hydrophobic force.