Characterization of an extended form of recombinant human insulin-like growth factor II. |
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| Authors: | B Hammarberg M Tally E Samuelsson H Wadensten E Holmgren M Hartmanis K Hall M Uhlén T Moks |
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| Affiliation: | Department of Biochemistry and Biotechnology, Royal Institute of Technology, Stockholm, Sweden. |
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| Abstract: | To investigate the biological role of variants of human insulin-like growth factor II (IGF-II), an extended form designated IGF-IIE21, with a molecular mass of 9.8 kDa, was produced in Escherichia coli as a stable and soluble secreted fusion protein. After site-specific cleavage of the affinity purified fusion protein, followed by purification using ion exchange and reversed phase chromatography, it could be demonstrated that IGF-IIE21 and IGF-II have similar or identical activities according to radioimmunoassay and radioreceptor assay. However, IGF-IIE21 showed only 1% growth promotion activity as compared with IGF-II in a clonal expansion assay using human K562 cells which lacks IGF-I receptors. These results suggest that this extended variant of IGF-II can bind to the receptor but has limited growth promoting activity. |
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