Sugiyama Y, Stolz A, Hershman J M, Kaplowitz N
Biochim Biophys Acta. 1984 Sep 28;801(2):184-8. doi: 10.1016/0304-4165(84)90066-7.
Dv protein and ligandin are two hepatic cytosolic proteins which bind organic anions, including endogenous thyroid hormones. Binding studies were performed using the ANS displacement technique to compare the binding of a variety of thyroid hormone analogues to purified organic anion binder and ligandin. Inhibition of ANS binding by these compounds was competitive. Both proteins bound L- and D-thyroxine with comparable affinity (Kd 30-45 microM), whereas ligandin bound 3',3',5-triiodo-L-thyronine, 3',3',5-triiodo-L-thyronine and most analogues with greater affinity. Nevertheless, the order of ligand affinities for both binders was highly correlated, suggesting that the nature of the binding site on both proteins is similar. The binding affinities of these organic anion binders are 2-3 orders of magnitude lower than an hepatic cytosolic thyroid binder reported by others, suggesting that ligandin and organic anion binder may not be important in intracellular thyroid hormone transfer.
Dv蛋白和配体蛋白是两种肝脏胞质蛋白，它们能结合包括内源性甲状腺激素在内的有机阴离子。使用ANS置换技术进行结合研究，以比较多种甲状腺激素类似物与纯化的有机阴离子结合蛋白和配体蛋白的结合情况。这些化合物对ANS结合的抑制作用具有竞争性。两种蛋白以相当的亲和力（解离常数Kd为30 - 45微摩尔）结合L-和D-甲状腺素，而配体蛋白以更高的亲和力结合3',3',5-三碘-L-甲状腺原氨酸、反式-3',3',5-三碘-L-甲状腺原氨酸和大多数类似物。然而，两种结合蛋白的配体亲和力顺序高度相关，这表明两种蛋白上结合位点的性质相似。这些有机阴离子结合蛋白的结合亲和力比其他人报道的一种肝脏胞质甲状腺结合蛋白低2 - 3个数量级，这表明配体蛋白和有机阴离子结合蛋白在细胞内甲状腺激素转运中可能并不重要。
