Abstract

A new method to estimate the butyrylcholinesterase (BChE, EC 3.1.1.8) activity by using capillary electrophoresis (CE) coupling with electrochemiluminescence (ECL) was described. The liberated N,N-dimethylethanolamine (DMEA) that produced by BChE catalyzing hydrolysis reaction of tetracine hydrochloride was used as ECL coreagent to enhance Ru(bpy)32+ ECL signals efficiently. The detection limit for DMEA was 1.98×10−8 M (S/N = 3), which was equal to that 6.6×10-10 units of BChE be used to catalyze tetracine hydrochloride for 30 min. The Michaelis constant Km (1.16×10-3 mol/L) and the maximum reaction velocity Vmax (2.71×10-7 mol/L/min) of BChE for tetracine hydrochloride were reported. Also, the reaction conditions including the concentration of metal ions, incubation temperature and pH were optimized. This method was successfully applied to detect BChE activity as a bio-marker in plasma and the results were in good agreement with that obtained by the clinical method.

Key words: capillary electrophoresis; electrochemiluminescence; butyrylcholinesterase; enzyme activity