Purification and Characterization of an Insulin-Like Growth Factor-Ii Variant from Human-Plasma

Hampton, B., Burgess, W. H., Marshak, D. R., Cullen, K. J., Perdue, J. F. (November 1989) Purification and Characterization of an Insulin-Like Growth Factor-Ii Variant from Human-Plasma. Journal of Biological Chemistry, 264 (32). pp. 19155-19160. ISSN 0021-9258

URL: http://www.ncbi.nlm.nih.gov/pubmed/2553732

Abstract

An insulin-like growth factor II variant (IGF-II variant) was purified from Cohn fraction IV1 of human plasma by ion exchange, gel filtration, and reversed-phase high pressure liquid chromatography. The amino-terminal sequence of the first 35 amino acid residues showed a replacement of Ser-29 of IGF-II with the tetrapeptide Arg-Leu-Pro-Gly of IGF-II variant. Peptides isolated and sequenced after digestion with endoproteinase Asp-N and endoproteinase Glu-C disclosed no differences with the sequence predicted from an IGF-II variant cDNA clone isolated by Jansen, M., van Shaik, F. M. A., van Tol, H., Van den Brande, J. L., and Sussenbach, J. S. (1985) FEBS Lett., 179, 243-246. The molecular ion of intact IGF-II variant was 7809.4 mass units, as measured by plasma desorption mass spectrometry. This is in close agreement with the molecular ion of 7812.8 mass units calculated from the determined sequence and indicates the entire amino acid sequence had been accounted for. Binding of IGF-II variant to purified insulin-like growth factor I (IGF-I) receptors demonstrated a 2-3-fold lower affinity for this receptor compared with IGF-I or IGF-II. The dissociation constants for IGF-I, IGF-II, and IGF-II variant are 0.23, 0.38, and 0.80 nM, respectively. In a growth assay, the concentration of IGF-II and IGF-II variant required to stimulate the half-maximal growth of MCF-7 cells was 4 and 13 nM, respectively. Finally, the amount of IGF-II variant that can be purified by this method constitutes approximately 25% of the total IGF-II isolated from Cohn fraction IV1 of human plasma.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > IGF
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > cDNA
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types
CSHL Authors:
Communities: CSHL labs
Depositing User: Gail Sherman
Date: November 1989
Date Deposited: 27 Jul 2017 18:27
Last Modified: 27 Jul 2017 18:27
Related URLs:
URI: http://repository.cshl.edu/id/eprint/34856

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