重组胰高血糖素样肽-1与人血清白蛋白融合蛋白的纯化及活性研究

利用构建的重组菌株Pichia pastoris GS115/GLP-1/HSA,在10L发酵罐中表达了胰高血糖素样肽-1与人血清白蛋白融合蛋白(GLP-1/HSA),表达量为63.6mg/L。发酵液经中空纤维柱浓缩、疏水层析、阴离子交换层析和凝胶过滤分离纯化,获得了较高纯度的GLP-1/HSA,经HPLC分析纯度达95.8%。进一步的体内活性分析结果表明,GLP-1/HSA不仅具有天然GLP-1的生物活性,而且在给药后4h仍能发挥显著性降血糖作用。以上结果表明,利用Pichia pastoris分泌型表达系统和建立的分离纯化方法,能获得大量较高纯度的GLP-1/HSA,为进一步研究和开发能够用于糖尿病临床治疗的长效GLP-1类似物奠定了基础。

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

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.