通过荧光法测定主要甲状腺激素代谢物3,3',5'-三碘-L-甲状腺原氨酸与牛血清白蛋白的结合特性。

Binding characteristics of a major thyroid hormone metabolite, 3,3',5'-triiodo-L-thyronine, to bovine serum albumin as measured by fluorescence.

作者信息

Okabe N, Mano N, Tahira S

机构信息

Faculty of Pharmaceutical Sciences, Kinki University, Osaka, Japan.

出版信息

Biochim Biophys Acta. 1989 Mar 24;990(3):303-5. doi: 10.1016/s0304-4165(89)80049-2.

DOI:10.1016/s0304-4165(89)80049-2

PMID:2923909

Abstract

The interaction between a major thyroid hormone metabolite, 3,3',5'-triiodo-L-thyronine and bovine serum albumin was investigated by fluorescence measurements. The apparent binding constants were obtained at various pHs assuming the equivalence and independence of the interaction sites on the protein from the fluorescence titration curves. The maximum binding was attained at pH 8.0, and the apparent binding constant was (5.28 +/- 0.13).10(5) M-1 with one binding site per albumin molecule. Thermodynamic parameters were also determined from the van't Hoff plot of the apparent binding constants at pH 7.5. The free energy change, enthalpy change and entropy change were -7.70 +/- 0.09 kcal.mol-1, -4.59 kcal.mol-1 and 10.2 e.u., respectively.

摘要

通过荧光测量研究了主要甲状腺激素代谢物3,3',5'-三碘-L-甲状腺原氨酸与牛血清白蛋白之间的相互作用。根据荧光滴定曲线，假设蛋白质上相互作用位点的等效性和独立性，在不同pH值下获得了表观结合常数。在pH 8.0时达到最大结合，每个白蛋白分子有一个结合位点时，表观结合常数为(5.28±0.13)×10⁵ M⁻¹。还从pH 7.5下表观结合常数的范特霍夫图确定了热力学参数。自由能变化、焓变和熵变分别为-7.70±0.09 kcal·mol⁻¹、-4.59 kcal·mol⁻¹和10.2 e.u.。