Stereoselective binding of the glucuronide of ketoprofen enantiomers to human serum albumin.
Stereoselective binding of the glucuronide of ketoprofen enantiomers to human serum albumin.
复制标题
DOI：
10.1016/0006-2952(94)90453-7
复制
发表时间：
1994-11
影响因子：
5.8
通讯作者：
N. Dubois;F. Lapicque;J. Magdalou;M. Abiteboul;P. Netter
中科院分区：
文献类型：
--
作者：
N. Dubois;F. Lapicque;J. Magdalou;M. Abiteboul;P. Netter
由于已知酰基葡萄糖醛酸苷会发生去结合，尤其是在人血清白蛋白（HSA）存在下，因此只有少数报告描述了其与血浆蛋白的可逆结合。本研究的目的是通过紫外圆二色谱等快速技术研究RandSketoprofen葡萄糖醛酸苷与人血清白蛋白的可逆结合。R酮洛芬葡萄糖醛酸苷的结合仅在340 nm处诱导外源性Cotton效应。Scatchard图分析表明，R酮洛芬及其葡糖苷酸与白蛋白的一个位点结合，结合常数分别为28.1 × 104和6.1 × 104 M −1。用二异丙基氟磷酸修饰一个酪氨酸残基，阻止配体进入白蛋白的位点I和II，也完全抑制了R酮洛芬及其偶联物的结合。用白蛋白结合位点的特异性探针进行的置换实验表明，R酮洛芬和葡萄糖醛酸苷结合于位点II而不是位点I。然而，Rketoprofen并没有被它的结合物所取代。Sketoprofen葡糖苷酸也与HSA结合，因为它降低了对映体结合物的结合。然而，这种代谢产物与白蛋白的结合并没有诱导足够大的外源性Cotton效应来确定结合常数。d-葡萄糖醛酸不与白蛋白的I或II位点结合。由于该基团的亲水性和/或庞大性，与R酮洛芬相比，该部分可能是HSA对R酮洛芬葡萄糖醛酸苷的亲和力较低的原因。
Since acyl glucuronides are known to undergo deconjugation, especially in the presence of human serum albumin (HSA), only a few reports have described their reversible binding to plasma proteins. The aim of this study was to investigate the reversible binding ofRandSketoprofen glucuronides to HSA by a rapid technique, such as ultraviolet circular dichroism. Binding ofRketoprofen glucuronide only induced an extrinsic Cotton effect at 340 nm. Scatchard plot analysis revealed thatRketoprofen and its glucuronide are bound to one site of albumin with an association constant of 28.1 × 104and 6.1 × 104M−1, respectively. Modification of one tyrosine residue by diisopropylfluorophosphate prevented the access of ligands to sites I and II of albumin, and also fully inhibited the binding ofRketoprofen and that of its conjugate. Displacement experiments with specific probes of albumin binding sites suggested thatRketoprofen and the glucuronide are bound to site II rather than site I. However,Rketoprofen was not displaced by its conjugate.Sketoprofen glucuronide is also bound to HSA, since it decreased the binding of the antipode conjugate. However, the binding of this metabolite to albumin did not induce an extrinsic Cotton effect large enough to determine the binding constants.d-Glucuronic acid did not bind to sites I or II of albumin. This moiety is likely responsible for the lower affinity of HSA for theRketoprofen glucuronide when compared to that forRketoprofen, due to the hydrophilicity and/or the bulkiness of this group.