Chemistry Department, University of Nebraska, Lincoln, NE 68588, USA.
Chemistry Department, University of Nebraska, Lincoln, NE 68588, USA.
J Chromatogr B Analyt Technol Biomed Life Sci. 2018 Oct 15;1097-1098:64-73. doi: 10.1016/j.jchromb.2018.09.001. Epub 2018 Sep 4.
Sulfonylurea drugs have significant binding to proteins in blood, with most of this binding believed to occur with human serum albumin (HSA). High performance affinity chromatography and affinity microcolumns containing immobilized HSA were used to investigate binding by the sulfonylurea drug chlorpropamide to normal HSA and glycated HSA, which is a modified form of HSA that has an increased serum concentration in diabetes. Experiments employing frontal analysis indicated that the binding by chlorpropamide gave a good fit to a two-site model for both normal HSA and glycated HSA samples that were representative of controlled or advanced diabetes. These interactions involved a set of moderate-to-high affinity sites and a set of lower affinity sites, with binding constants in the range of 6.2-9.9 × 10 M and 0.18-0.57 × 10 M, respectively, at pH 7.4 and 37 °C. Competition studies utilizing a zonal elution format demonstrated that chlorpropamide could interact at both Sudlow sites I and II of HSA, with affinities in the range expected for the moderate-to-high affinity sites of this drug. The affinity of chlorpropamide at Sudlow site I had a small increase of up to 1.2-fold when comparing the normal HSA and glycated HSA samples. Chlorpropamide gave a larger 1.4- to over 1.5-fold increase at Sudlow site II when the affinity of this drug was compared between normal HSA and the same samples of glycated HSA. These results were compared to those obtained previously with other sulfonylurea drugs to help determine how glycation can change the overall and site-selective binding strength of these drugs with HSA at levels of protein modification that are seen in patients with diabetes.
磺酰脲类药物与血液中的蛋白质有显著的结合，其中大部分结合被认为发生在人血清白蛋白（HSA）上。高分辨率亲和色谱和含有固定化 HSA 的亲和微柱被用于研究磺酰脲类药物氯丙嗪与正常 HSA 和糖化 HSA 的结合，糖化 HSA 是 HSA 的一种修饰形式，在糖尿病患者的血清中浓度增加。采用前沿分析的实验表明，氯丙嗪的结合很好地符合了正常 HSA 和糖化 HSA 样本的双位点模型，这些样本代表了控制或晚期糖尿病。这些相互作用涉及一组中等到高亲和力的位点和一组低亲和力的位点，在 pH 值为 7.4 和 37°C 时，结合常数分别在 6.2-9.9×10 M 和 0.18-0.57×10 M 范围内。利用区带洗脱格式进行的竞争研究表明，氯丙嗪可以与 HSA 的 Sudlow 位点 I 和 II 相互作用，亲和力在该药物中等到高亲和力位点的预期范围内。与正常 HSA 和糖化 HSA 样本相比，氯丙嗪在 Sudlow 位点 I 的亲和力增加了 1.2 倍左右。当比较正常 HSA 和相同的糖化 HSA 样本中该药物的亲和力时，氯丙嗪在 Sudlow 位点 II 的亲和力增加了 1.4 到 1.5 倍以上。将这些结果与以前用其他磺酰脲类药物获得的结果进行比较，有助于确定糖化如何改变这些药物与 HSA 的整体和位点选择性结合强度，在糖尿病患者中可以看到蛋白质修饰的水平。
