Abstract: In this article, the interactions between hirudin and thrombin, and that between heparin and thrombin were investigated by using capillary electrophoresis. The binding constant between hirudin and thrombin was calculated to be 7.85×10⁵ L/mol. A capillary zone electrophoretic method was applied to determine the interactions between natural products and thrombin. The samples containing the natural extractions and thrombin at various ratios were incubated at 25 ℃ and then were separated by CZE with Tris-acetate buffer at pH=7.2. Each run could be accomplished within 10 min. The experimental results show that the reported method by capillary zone electrophoresis for the determination of the interactions between natural products and thrombin is powerful, sensitive and fast, requires less amounts of reagents, and further, it can be employed as a reliable alternative to other methods.

Key words: Capillary electrophoresis(CE), Thrombin, Biomolecular interactions, Drug screening