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Source / Purification

Recombinant human IGF-I (hIGF-I) Gly49-Ala118 (Accession #P01343) was produced in E. coli at Cell Signaling Technology.

Product Description


>98% as determined by SDS-PAGE of 6 μg reduced (+) and non-reduced (-) recombinant hIGF-I. All lots are greater than 98% pure.

Molecular Formula:

Recombinant hIGF-I has a Met on the amino terminus and has a calculated MW of 7,785. DTT-reduced and non-reduced protein migrate as 6 kDa polypeptides. The expected amino-terminal MGPET of recombinant hIGF-I was verified by amino acid sequencing.


The bioactivity of recombinant hIGF-I was determined in a cell proliferation assay using primary human dermal fibroblasts. The ED50 of each lot is between 2-8 ng/ml.


Less than 0.01 ng endotoxin/1 μg hIGF-I.

Product Usage Information


With carrier: Lyophilized from a 0.22 μm filtered solution of 20 mM citrate, pH 3.0 containing 100 mM NaCl and 20 μg BSA per 1 μg hIGF-I. Carrier free: Lyophilized from a 0.22 μm filtered solution of 20 mM citrate, pH 3.0 containing 100 mM NaCl.

Storage: Stable in lyophilized state at 4°C for 1 year after receipt. Sterile stock solutions reconstituted with carrier protein are stable at 4°C for 2 months and at -20°C for 6 months. Avoid repeated freeze-thaw cycles.Maintain sterility. Storage at -20°C should be in a manual defrost freezer.

Most circulating endocrine acting IGF-I is produced by hepatocytes, and paracrine or autocrine acting IGF-I is produced by defined cell types within specific tissues (1,2). Many neoplastic cells produce IGF-I, which regulates a number of cellular processes including energy metabolism, proliferation, and cell survival (3,4). IGF-I activity is regulated by one or more of the six extracellular IGF-binding proteins (IGFBPs). IGFBPs bind to IGF-I and most inhibit IGF-I binding to IGF-I receptor (IGFIR) (1,2). Some IGFBPs may increase cell responses to IGF-I. Binding of IGF-I to IGFIR activates the Akt, JNK, and Erk pathways (2). IGF-I and IGFIR are frequently expressed by cancer cells and may contribute to the proliferation and viability of a number of cancer types (1,2).

1.  Pollak, M. (2008) Nat Rev Cancer 8, 915-28.

2.  Chitnis, M.M. et al. (2008) Clin Cancer Res 14, 6364-70.

3.  Karey, K.P. and Sirbasku, D.A. (1988) Cancer Res 48, 4083-92.

4.  Small, T.W. and Pickering, J.G. (2009) J Biol Chem 284, 24684-95.

Entrez-Gene Id 3479
Swiss-Prot Acc. P05019

For Research Use Only. Not For Use In Diagnostic Procedures.
Cell Signaling Technology is a trademark of Cell Signaling Technology, Inc.

Human Insulin-like Growth Factor I (hIGF-I)