Characterization of interactions between methoxatin disodium salt and human serum albumin by pressure‐assisted capillary electrophoresis/frontal analysis and circular dichroism spectroscopy

Abstract

Pressure-assisted capillary electrophoresis (PACE)/frontal analysis (FA) and circular dichroism spectroscopy were utilized to investigate the interactions between methoxatin disodium salt (PQQ-2Na) and human serum albumin (HSA). With the PACE/FA method, sodium phosphate buffer solution (67 mm, pH 7.4) was used as the background electrolyte. Hydrodynamic injection at 50 mbar for 50 s and external pressure of 50 mbar were applied. The binding constant and the number of primary binding sites to HSA were obtained under fixed concentration of PQQ-2Na (100 µm) and increasing HSA concentration (0~475 µm). The thermodynamic parameters characterized the main acting forces of hydrophobic and electrostatic interactions. The displacement experiments using phenylbutazone and flurbiprofen as ligand markers suggested that the binding site was the Sudlow site I of the HSA molecule. Circular dichroism spectroscopy was further employed to evaluate the conformation changes of HSA under the interaction of PQQ-2Na. This work provides comprehensive information for understanding the interactions between PQQ-2Na and HSA.

Enantioresolution and Binding Affinity Studies on Human Serum Albumin: Recent Applications and Trends

“…Table 5 showed different studies that have been reported over the years for the evaluation of the binding affinity of HSA of numerous drugs and other bioactive compounds using CE techniques. Many studies focused on the individual binding parameters for each compound/enantiomer [153,155,161] while others also described competitive studies between compounds to the binding sites of HSA [156,157,159]. Furthermore, most of these studies were enantioselective studies where the differences in binding of each enantiomer of the analyzed compounds to HSA were evaluated and compared using, many of them, HSA as a chiral selector [150,152,154,155].…”

Applicability of capillary electrophoresis‐frontal analysis for displacement studies: Effect of several drugs on l‐tryptophan and lidocaine binding to human serum albumin

“…The displacement studies were performed by using several methods, including ultrafiltration [10], ED [11], crystallographic studies [12], CD [13], fluorescence spectroscopy [14, 15], molecular modeling [16], high‐performance affinity chromatography [17], and capillary electrophoresis (CE) in different modes including affinity CE, vacancy affinity CE, partial filling CE, near‐infrared dye‐displacement CE or CE‐FA [1, 18–21]. Despite the fact that CE‐FA method is widely used for binding parameters determination only a few research groups reported about its applicability for displacement studies [22–29]. CE‐FA method was chosen for these measurements in view of its many benefits, which include small sample consumption, robustness and the possibility of high‐throughput screening [30,31].…”

Application of capillary electrophoresis-frontal analysis for comparative evaluation of the binding interaction of captopril with human serum albumin in the absence and presence of hydrochlorothiazide

“…However, some disadvantages of these analytical techniques limit their applications, such as long equilibrium time and large sample consumption. Capillary electrophoresis (CE) has been proved to be more convenient and cost-effective for the interaction study [5,[12][13][14][15][16][17]. There are several modes of CE have been proposed for the quantitative assessment of drug-protein interactions, such as affinity capillary electrophoresis, the Hummel-Dreyer method, vacancy peak method, vacancy affinity capillary electrophoresis, and capillary electrophoresis-frontal analysis (CE-FA) [11,18].…”