Abstract:Chicken liver esterase was purified using three different methods: including fractional ammonium sulfate precipitation, fractional ammonium sulfate precipitation + dialysis, and fractional ammonium sulfate precipitation + exclusion chromatography. Four types of organophosphate with different structures and carbamate pesticides were used to detect the effects of these purification methods on the sensitivity of purified chicken liver esterase to pesticide inhibition. The results showed that the sensitivity of the esterase to pesticide increased significantly after purification. Compared with crude esterase, pesticide inhibition rates of purified esterase increased by 6.49%~11.30% with fractional ammonium sulfate precipitation, 14.30%~26.26% with fractional ammonium precipitation + dialysis, and 10.95%~39.87% with fractional ammonium precipitation + exclusion chromatography. The recovery rates of sensitive esterase were 86.07%~89.96%, 66.60%~73.57%, and 33.01%~41.62%, respectively. Due to the low recovery of sensitive esterase obtained by fractional ammonium sulfate precipitation + exclusion chromatography, fractional ammonium sulfate precipitation + dialysis is preferable for the large-scale preparation of enzymes. In addition, the esterase sensitive to the four different types of pesticides was always in the same fraction, regardless of the purification method. Thus, the sensitive esterase might be one or several kinds of esterases with similar solubility and molecular weight.
