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Heat labile alkaline phosphatases (APs) are widely used in biomedical research for they can easily be heat inactivated once they have done their job. Here we reported a novel method for high-level production of recombinant psychrophilic Antarctic bacterium strain TAB5 alkaline phosphatase (TAP) in Escherichia coli. We synthesized the whole TAP gene according to the synonymous codon choice that is optimal for the E. coli translational system. Then the gene was cloned into pT7 expression vector, expressed in BL21 (DE3) pLysS strain by auto-induction system. The recombinant protein was purified by Ni–NTA affinity chromatography and anion exchange chromatography. The typical yield was 90.9mg protein from 16.2g wet cells in 1L culture medium with the purity over 99%, 340 times as many mg/L (and 21 times the mg/g cells) compared to previous methods. The dephosphorylation activity assay showed that …