Expressing Optimization of argE Gene and Mechanism Analysis of Zn~(2+) Feeding Time and Its Concentration

The cellular location of target gene argE expressed in recombinant BL21(DE3)-pET22b-argE was determined.The effects of Zn2+ effect feeding time and concentration on the biomass production and gene expression product activity were studied.The mechanism of Zn2+ effect was analyzed.The results showed that N-acetylornithine deacetylase coded by argE gene was over expressed and most of it was expressed as insoluble inclusion body,only a little as soluble expression.1.0 g/L Mg2+ concentration improved both the biomass production and enzyme activity greatly.With different concentrations and feeding times,Zn2+ could bring about different influences.In contrast to the inhibition of feeding Zn2+ at the cultivation beginning,addition of 1.0 mg/L Zn2+ after inducing for 2.5 h with 1.0% lactose reduced the inhibition on the growth and increased the enzyme activity.SDS-PAGE analysis and enzyme activity measurement proved that Zn2+ did not influence the expression rate,but the catalyst site of recombinant NAOase.