Title: Purification and characterization of recombinant human insulin‐like growth factor II (IGF‐II) expressed as a secreted fusion protein in Escherichia coli
Abstract: Human insulin‐like growth factor II (IGF‐II) was produced in an Escherichia coli ompT strain as a 22.5‐kDa fusion protein. IGF‐II was fused to the carboxy‐terminal of a synthetic 15‐kDa IgG‐binding protein, originating from staphylococcal protein A, via a unique methionine linker. During fermentation, the fusion protein was exported to the growth medium at levels exceeding 900 mg/liter and subsequently affinity purified on IgG Sepharose followed by ion exchange on S Sepharose. After chemical cleavage with CNBr, yielding an authentic IGF‐II molecule, the recombinant IGF‐II was purified to homogeneity by a two step procedure involving ion‐exchange and reverse‐phase HPLC. A substantial fraction of the secreted protein was found to be biologically active, eliminating the need for complex refolding procedures. The yield of highly purified and biologically active IGF‐II was 5–7 mg/liter of fermenter broth. The IGF‐II produced by this method displayed biochemical, immunological, receptor binding, and biological activity properties equal to those of native IGF‐II isolated from human serum.
Publication Year: 1991
Publication Date: 1991-06-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
Access and Citation
Cited By Count: 12
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot