Comparison and theoretical modeling of capillary electrophoresis analysis for the interaction between caffeine and serum proteins

The method for analyzing the interaction between caffeine and human serum albumin (HSA) was established by capillary electrophoresis. Under physiological conditions, the interaction between ligand (caffeine)-receptor (HSA) was studied with frontier-analysis (FA) method, Hummel-Dreyer (HD) method and plug-plug kinetic (PPK) method. The interaction parameters of caffeine-HSA system were obtained using non-linear equation, Scatchard equation and Klotz equation. The results showed that FA, HD and PPK methods were suitable for caffeine-HSA system, among them, HD method was the best, and the Non-linear equation was the best theoretical model to caffeine-HSA system. Interaction parameter tests showed that caffeine-HSA interaction was a single site interaction and the binding stability was moderate. The mechanism of caffeine-HSA interaction has been elucidated, which can provide valuable information for further research of alkaloids.