Expression of human globular adiponectin-glucagon-like peptide-1 analog fusion protein and its assay of glucose-lowering effect in vivo.

In this study, human globular adiponectin-glucagon-like peptide-1 analog (gAd-GLP-1-A) fusion protein was expressed and its glucose-lowering effect was measured in vivo. We constructed a prokaryotic expression vector PET28a-gAd-GLP-1-A and transformed the vector into Escherichia coli BL21 (DE3). A recombinant fusion protein of about 25KD was expressed from BL21 (DE3) cells after isopropylthio-β-D-galactoside induction. This protein was N-terminal His-tagged gAd-GLP-1-A fusion protein. Most of the protein was expressed in inclusion body. The fusion protein in inclusion body was purified by using High-Affinity Nickel Iminodiacetic Acid Resin and refolded in urea gradient refolding buffer. The refolded protein was incubated with enterokinase to remove the N-terminal His-tag. The fusion protein without His-tag is gAd-GLP-1-A fusion protein, which exhibited significant glucose-lowering effect in diabetic mice.