Characterization of interactions between methoxatin disodium salt and human serum albumin by pressure-assisted capillary electrophoresis/frontal analysis and circular dichroism spectroscopy.
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.
Laboratory of Pharmaceutical Analysis, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, People's Republic of China.
Lijuan
L
Zhao
Dongying
D
Chen
D002942:Circular Dichroism / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007700:Kinetics; D045542:PQQ Cofactor / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D015203:Reproducibility of Results; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
D012709:Serum Albumin; D045542:PQQ Cofactor
capillary electrophoresis frontal analysis; circular dichroism; drug binding; human serum albumin; methoxatin disodium salt