Comparison expressions of γ-glutamyl transpeptidase in Escherichia coli from two pET plasmids using lactose as inducer

The γ-glutamyl transpeptidase encoding gene(ggt)from E.coli K-12 was amplified by PCR and cloned into pET28(a)and pET32(a)successfully.Both lactose and IPTG could induce the expression of γ-glutamyl transpeptidase in E.coli from pET plasmids efficiently.After adding lactose,the low culture temperature could increase the expression level of soluble target protein,but the solubility of γ-glutamyl transpeptidase protein in E.coli BL21(DE3)harboring pET32(a)/γ-ggt was 3-fold higher than that in E.coli BL21(DE3)harboring pET28(a)/γ-ggt,and the specific activity of the enzyme in recombinanu E.coli BL21(DE3)harboring pET32(a)/γ-ggt was 1.6-fold higher.Overall,lactose could be a promising inducer in the future large scale production of recombined γ-glutamyl transpeptidase.