Purification and Characterization of Glucagon-Like Peptide-1 and Human Serum Albumin Fusion Protein Expressed in Pichia pastoris

Abstract:

A fusion protein of glucagons-like peptide-1 and human serum albumin (GLP-1/HSA) was expressed and secreted into the fermentation broth with recombinant Pichia pastoris. The productivity of expressed GLP-1/HSA could reach 63.6mg/L in 10L fermentor. After concentrated with hollow-fiber ultrafiltration membrane, GLP-1/HSA was purified from fermentation broth by hydrophobic chromatography, negative ion exchange chromatography and gel filtration chromatography in turn. The HPLC analysis showed that the purified GLP-1/HSA had an overall purity of 95.8%. Furthermore, the analysis of in vivo activity indicated that GLP-1/HSA had the bioactivity of native GLP-1, and could significantly reduce blood glucose level 4h after intraperitoneal administration. It was concluded that a great deal of GLP-1/HSA with higher purity could be harvested by Pichia pastoris expression system and the established purification methods. Preliminary studies show a new potential for developing the long-acting GLP-1 analogs for clinical applications.