Quantitative evaluation of the interaction between pUC19DNA and ovalbumin by capillary zone electrophoresis

Capillary zone electrophoresis (CZE) was used to study the interaction between pUC19DNA (pUC19) and ovalbumin (Ova). Samples containing pUC19 and Ova at various ratios were incubated at room temperature and were then separated by CZE with tris-acetate buffer at pH 7.2. Reduction in ultraviolet (UV) absorbance of pUC19 was due to the decrease of free pUC19 after binding to Ova. The binding constant of the interaction calculated from the Scatchard plot was (1.46 ± 0.15)×105 M–1. The use of polyacrylamide-coated capillary showed better effects than that of uncoated capillary. The results show that it is important to keep a constant ionic strength in the samples to in order to obtain accurate quantitative data in binding assays by CZE.