Preparation and Detection of Acetylcholinesterase by One-step Electrochemical Deposition

The gene encoding acetylcholinesterase (AChE) was cloned from Kunming mouse brain. The full length cDNA was 1845 bp, corresponding to a protein of 614 amino acids. The specific protein bend with molecular masses of 68 kDa was observed by SDS-PAGE analysis. After purified 2,400 fold, it was exhibited the specific activity of 742 U/mg. Then, an interface embedded in situ gold nanoparticles (AuNPs) and biotin in chitosan hydrogel was constructed by one-step electrochemical deposition. A.C. impedance was used to characterize this interface. The immobilized AChE, as a model, provided a quantitative measurement of organophosphate pesticide. Under the optimal experimental conditions, the inhibition of dimethoate was proportional to its concentrations in the range of 0.05 to 15 mu g/mL with detection limit of 0.001 mu g/mL.