Inhibition Assay of Theophylline by Capillary Electrophoresis/Dynamic Frontal Analysis on the Hydrolysis of p-Nitrophenyl Phosphate with Alkaline Phosphatase
A novel inhibition assay is proposed by capillary electrophoresis/dynamic frontal analysis (CE/DFA). When a substrate of p-nitrophenyl phosphate and an inhibitor of theophylline were tandemly introduced into the capillary containing alkaline phosphatase as an enzyme, two plateau signals were detected in the electropherogram. A higher plateau is based on the CE/DFA without inhibition, and a suppressed plateau is formed under the inhibition while the substrate zone passing through the inhibitor zone. Inhibition constant was successfully determined through the two plateau heights
