Characterization of the heterogeneous adsorption of three drugs on immobilized bovine serum albumin by adsorption energy distribution

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 1125; p. 121727
• Main Authors: Sun, Huanmei, Liu, Jiajun, Li, Yifei, Wang, Jing, Zhang, Yajun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2019
• Subjects: Adsorption; Adsorption energy distribution; affinity chromatography; Animals; Binding Sites; Bovine serum albumin; Cattle; Chromatography, Affinity; dialysis; energy; ephedrine; Ephedrine - chemistry; Frontal affinity chromatography; Protein Binding; Serum Albumin, Bovine - chemistry; Site-specific competitive study; tryptophan; Tryptophan - chemistry; ultrafiltration; warfarin; Warfarin - chemistry; AED; PBS; DD; Bovine serum albumin; Site-specific competitive study; EM; Adsorption energy distribution; FAC; HPAC; FS; EDM; BSA; UF; RCD; RSS; Frontal affinity chromatography; SPR; CE/FA; ITC; QCM; GFFA; ED
• ISSN: 1570-0232; 1873-376X; 1873-376X
• DOI: 10.1016/j.jchromb.2019.121727

Characterization of the heterogeneity of a protein surface is important for understanding the binding mechanism of a drug to the protein. A systematic methodology of integrated adsorption energy distribution (AED) calculation with the Scatchard plot was used to characterize the heterogeneous binding of drugs to bovine serum albumin (BSA). Frontal affinity chromatography (FAC) was applied to generate the adsorption data of three drugs on the immobilized BSA column. The concave Scatchard plots cannot distinguish the heterogeneous model between Toth and bi-Langmuir. The calculation of AED profiles allowed the accurate selection of adsorption models to reveal the physical sense of the drugs. Warfarin-BSA complex proved to be the bi-Langmuir model with association constants of 6.6 × 105 M−1 and 2.4 × 103 M−1, respectively. These results were highly consistent with traditional frontal analysis, ultrafiltration, and dynamic dialysis. Applying the AED related method, we achieved multiple and single kinds of binding sites for ephedrine-BSA and L-tryptophan-BSA complexes. Site-specific competitive studies exhibited non-competitive binding of ephedrine with warfarin or L-tryptophan on BSA, underlining that the location of ephedrine binding sites in the subdomain IIIB of BSA. This method permits an accurate heterogeneous characterization of drugs on a protein surface and has great potential in the reliable drug-protein interaction analysis. •Drug-protein interaction analysis was achieved by adsorption energy distribution (AED).•AED profile allowed selection of better adsorption model to reveal physical sense of drugs on BSA.•Site specific competitive study provided indispensable proof of drug binding site.