Loun B, Hage D S
Department of Chemistry, University of Nebraska, Lincoln 68588.
J Chromatogr. 1992 Sep 2;579(2):225-35.
A high-performance affinity column containing immobilized human serum albumin (HSA) was used to study the binding of thyroxine at the warfarin and indole sites of HSA. Frontal analysis, using R-warfarin and L-tryptophan as probes for these sites, demonstrated that the immobilized HSA had binding behavior equivalent to that observed for HSA in solution. By injecting R-warfarin or L-tryptophan in the presence of excess thyroxine, it was found that thyroxine was binding directly to both types of site. The warfarin and indole sites had relatively strong binding for thyroxine, with association constants at 37 degrees C of 1.4 x 10(5) and 5.7 x 10(5) M-1, respectively. The value of delta G for these sites ranged from -7 to -8 kcal/mol and had a significant entropy component. The techniques used in this study are not limited to thyroxine-HSA interactions, but should also be valuable in examining the site-specific binding of other drugs and hormones to HSA.
使用含有固定化人血清白蛋白（HSA）的高性能亲和柱研究甲状腺素在HSA的华法林和吲哚位点的结合情况。采用R-华法林和L-色氨酸作为这些位点的探针进行前沿分析，结果表明固定化HSA的结合行为与溶液中HSA的结合行为相当。通过在过量甲状腺素存在下注入R-华法林或L-色氨酸，发现甲状腺素直接结合到这两种类型的位点。华法林和吲哚位点对甲状腺素具有相对较强的结合力，在37℃时的缔合常数分别为1.4×10⁵和5.7×10⁵ M⁻¹。这些位点的ΔG值范围为-7至-8 kcal/mol，且具有显著的熵成分。本研究中使用的技术不仅限于甲状腺素与HSA的相互作用，在研究其他药物和激素与HSA的位点特异性结合方面也应具有重要价值。
