Expression and Bioactivites of Recombinant Human Glucagon-like Peptide-1 / 中国生物工程杂志

ABSTRACT

The synthesized full-length hGLP-1 gene was cloned into pET-32a(+) to get the recombinant plasmid pET32-GLP-1, which could express a fusion protein containing thioredox, hexahistidine, and rhGLP-1 consecutively. The recombinant plasmid containing hGLP-1 was transformed into E.coli BL21 (DE3) and expressed by IPTG induction. The fusion protein was purified from lysates with Ni?IDA His?Bind affinity chromatography. rhGLP-1 with the purity of 90% was achieved after enterokinase digestion, Ni?IDA His?Bind affinity chromatography again, then was concentrated by ultrafiltration. The purified rhGLP-1 showed a single band on IEF gel with an isoelectric point between pH5.2 and pH5.85. ESI mass spectrometry showed that the molecular weight was 3355.0kDa as expected. rhGLP-1 was digested with trypsin followed by mass analysis and the peptide mapping produced two expected fragments with the molecular weights of 2097.7kDa and 1005.5kDa, respectively. The purified rhGLP-1 also showed obvious biological activity for both lowering plasma glucose and stimulating insulin secretion in mice.