荧光法研究钍与牛血清白蛋白的结合反应

Studies on the Interaction Between Thorium and Bovine Serum Albumin by Fluorescence Method

用荧光法和同步荧光法研究了在模拟生理条件下锕系元素钍(Th)与牛血清白蛋白(BSA)的结合反应,结果表明Th与BSA的结合数为1,结合常数为1.70×104.求得Th结合位置与BSA分子212位色氨酸残基间的距离为0.67nm,发现Th使BSA的Trp残基微环境更加紧缩疏水,而酪氨酸残基微环境则更加外露.经比较发现Th与BSA的结合反应程度和对BSA构象的影响程度远大于稀土离子与BSA的结合.

The interaction between thorium （Th） and bovine serum albumin （BSA） was studied by fluorescence spectroscopy and synchronous fluorescence spectroscopy. The results show that the binding number between Th and BSA is 1 ,and the association constant is 1.70×10^4;the distance between 212-tryptophan （Trp） residue of BSA and a bound thorium was calculated and was found to be about 0.67 nm; after Th combined to BSA, the Trp microenvironment seemed to be more hydrophobic, however, the tyrosine （Tyr） residue microenvironment exposed than before;through the comparison,it is found that the combination of Th and BSA results in the stronger reaction and deeper influence on BSA＇s conformational change than that of rare earth ions and BSA.