PEGylation of Proteins in Organic Solution: A Case Study for Interferon beta-1b

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• 作者：Fei Peng ; Yinjue Wang ; Lijing Sun ; Yongdong Liu ; Tao Hu ; Guifeng Zhang ; Guanghui Ma ; Zhiguo Su
• 刊名：Bioconjugate Chemistry
• 出版年：2012
• 出版时间：September 19, 2012
• 年：2012
• 卷：23
• 期：9
• 页码：1812-1820
• 全文大小：392K
• 年卷期：v.23,no.9(September 19, 2012)
• ISSN：1520-4812

文摘

Conventional protein PEGylation is carried out in aqueous solution. However, some hydrophobic proteins seem to be stable in organic solution. In this study, a novel approach of PEGylating IFN-尾-1b in an organic solution of 2-butanol (2-BuOH) was investigated. Compared with protein PEGylation in aqueous solution, the overall modification yields increased more than 37%, while the yield of mono-PEGylated products could be increased by 36%. Furthermore, the PEGylated IFN-尾-1b, which was obtained in organic solution, demonstrated 18% more antiviral potency than those derived from aqueous solution. The PEGylation step could be directly connected to the previous protein separation step for process integration. Dynamic light scattering (DLS) and atomic force microscope (AFM) analysis revealed that IFN-尾-1b formed aggregates both in water and in 2-BuOH solutions. However, the aggregates were much smaller and more homogeneous in 2-BuOH than those in aqueous solution, thereby providing larger solvent accessible protein surfaces, which resulted in a more productive PEGylation process. In addition, the results of circular dichroism (CD), fluorescence spectra, and peptide mapping suggested that the increased bioactivity came from the difference in PEGylation site distribution due to solution environment that induced conformational discrepancy. The results of this study show that PEGylation of IFN-尾-1b in organic solution is a facile and efficient process, which might find applications for other hydrophobic proteins.