Analytical Sciences

Efficient Preservation of Acetylcholinesterase at Room Temperature for Facile Detection of Organophosphorus Pesticide

Wenzhi TANG,*,**,*** Jingxian YANG,*,**,*** Fei WANG*,**,*** and Zhonghong LI*,**,***

*College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
**Laboratory of Quality & Safety Risk Assessment for Agro-products (Yangling), Ministry of Agriculture, Yangling, Shaanxi 712100, China
***National Engineering Research Center of Agriculture Integration Test (Yangling), Yangling, Shaanxi 712100, China

A simple and inexpensive strategy is reported to facilitate the detection of an organophosphorus pesticide by acetylcholinesterase (AChE). Pullulan is able to preserve AChE at room temperature, but the activity of conserved AChE varies significantly depending on the time, stir and volume of solution to dissolve it. The reason is that AChE entrapped in pullulan tablet remains in an inactive state to avoid denaturalization and deactivation. There is a reactivation process to gradually recover the enzyme activity during dissolution of the tablet. Stirring would interrupt this procedure and lead to a loss of enzyme activity. Dissolution of the tablet for 5 min with a volume of 15 μL could facilitate full recovery of AChE activity. The feasibility of activated AChE for organophosphorus pesticide detection was evaluated using malaoxon. These results contribute to the understanding of preservation mechanism by pullulan and the development of easy-to-use enzyme assays.

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