Expression, purification and characterization of recombinant human globular domain of adiponectin

Purpose: To obtain bioactive globular domain of human adiponectin. Methods: cDNA encoding human globular domain of adiponectin (gAPN) was amplified by PCR, and cloned in the expression vector pET28a(+). The recombinant expression plasmid pET28a(+)-gAPN was transformed into E. coli BL21 (DE3). When A ₆₀₀ (nm) reached 0.6, this transformant was induced for expression of recombinant protein by IPTG. Recombinant protein was obtained after denaturation, purification by Ni⁺-affinity chromatography and renaturation. The bioactivity of recombinant protein was evaluated by Streptozocin (STZ)-induced hyperglycemia model. Results: After induction for 3 hours by IPTG, the recombinant protein was over 30% of total bacterial protein. The recombinant protein was expression in form of inclusion bodies. After purification, SDS-PAGE analysis indicated that molecular weight of recombinant protein was about 17 000 and the purity was up to 90%. Western blot indicated that recombinant protein could react with anti-APN polyclonal antibody. The recombinant protein could significantly reduce the level of blood glucose in STZ-induced hyperglycemia model. Conclusions: We successfully expressed human globular domain of adiponectin (gAPN) in E. coli BL21 (DE3) and obtained the bioactive protein.