Abstract: To construct the prokaryotic expression plasmid of human Sadenosylmethionine decarboxylase(SAMDC) α subunit, and to induce and purify the recombined SAMDCα protein. Methods: A 801?bp cDNA spanning the coding region of SAMDC α subunit was amplified by RTPCR and subcloned into prokaryotic expression vector pTriEx4. The resulted vector pTriEx4SAMDCα was transformed into competence E.coli JM109(DE3), then was induced by IPTG. The protein was verified by SDSPAGE and Western blot with anti His•Tag monoclonal antibody. The fusion protein including 6×His•Tag was purified by NiNTA chromatographic column. Results: A 801?bp cDNA was successfully amplified by RTPCR from colorectal cancer cells and confirmed by sequence. The prokaryotic expression plasmid pTriEx4SAMDCα was successfully constructed, which was identified by digestion and sequence. An approximate 32kDa exogenous protein was observed on the SDSPAGE and Western blot showed that the protein including 6×His•Tag was purified successfully by NiNTA affinity chromatography. Conclusion: The prokaryotic expression plasmid pTriEx4SAMDCα is constructed correctly and the fusion protein is expressed and purified successfully.

Key words: S-adenosylmethionine decarboxylase(SAMDC), Colorectal neoplasms, Prokaryotic expression