Tb^（3＋）探针法研究蛇毒中纤溶组分的Ca^（2＋）结合环境

A Study of Combining Surroundings of Ca￣(2+) inFibrinolytic Principle of the Venoms in Agi-strodon Acutus Using Tb￣(3+)as a FluorescentProbe.

采用Ｔｂ￣（３＋）作为荧光探针研究了皖南尖吻蝮蛇蛇毒中纤溶组分中钙离子的结合环境。实验表明每个纤溶组分中含有一个高亲和点。钙离子位于发色团色氨酸（Ｔｒｐ）附近，并可能和苯丙氨酸（Ｐｈｅ）结合，在不同波长的激发下能产生Ｔｒｐ→Ｔｂ￣（３＋），Ｔｒｎ→Ｔｂ￣（３＋）→ｐｈｅ，Ｔｂ￣（３＋）→ｐｈｅ和Ｔｂ￣（３＋）→Ｔｒｐ之间的能量转移。Ｔｂ￣（３＋）位于Ｔｒｐ附近并可能与Ｐｈｅ结合。计算表明Ｔｂ￣（３＋）与Ｔｒｐ之间的距离约为５．６６Ａ。

Ⅲ)as a fluorescent probe was used tostudy the surroundings of metal ions in FP(fibrinolytic principle).There is a high affinitysite of Ca￣(2+) in every FP molecule and Ca￣(2+) ionsare located near the Trp.When Tb (Ⅲ)-FPwas excited by 222nm and 233nm. it is possi-ble that energy transfer occurs are as follows:Trp→Tb￣(3+),Trp→Tb￣(3+)→Phe,Tb￣(3+)→Phe,Tb￣(3+)→Trp.These results indicate that Phemay combine with Tb (Ⅲ).The results of cal-culations indicate that the distance betweenTrp and Tb (Ⅲ) is atout 5.56A.