• Purity

  >97%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured in a serum-free cell proliferation assay using MCF‑7 human breast cancer cells. Karey, K.P.     et al. (1988) Cancer Research     48:4083. The ED    ₅₀ for this effect is 0.4-2 ng/mL.

• Source

  E. coli-derived Gly33-Ala102

• Accession #

• N-terminal Sequence    
  Analysis

  Gly33

• Predicted Molecular Mass

  7.6 kDa

Data Images

Background: IGF-I

Insulin-like growth factor I, also known as somatomedin C, is the dominant effector of growth hormone and is structurally homologous to proinsulin. Mouse IGF-I is synthesized as two precursor isoforms with alternate N- and C-terminal propeptides (1). These isoforms are differentially expressed by various tissues (1). The 7.6 kDa mature IGF-I is identical between isoforms and is generated by proteolytic removal of the N- and C-terminal regions. Mature mouse IGF-I shares 94% and 99% aa sequence identity with human and rat IGF-I, respectively (2), and exhibits cross-species activity. It shares 60% aa sequence identity with mature mouse
IGF-II. Circulating IGF-I is produced by hepatocytes, while local IGF-I is produced by many other tissues in which it has paracrine effects (1). IGF-I induces the proliferation, migration, and differentiation of a wide variety of cell types during development and postnatally (3). IGF-I regulates glucose and fatty acid metabolism, steroid hormone activity, and cartilage and bone metabolism (4 - 7). It plays an important role in muscle regeneration and tumor progression (1, 8). IGF-I binds
IGF-I R, IGF-II R, and the insulin receptor, although its effects are mediated primarily by IGF-I R (9). IGF-I association with IGF binding proteins increases its plasma half-life and modulates its interactions with receptors (10).

• References:

1. Philippou, A. et al. (2007) In Vivo 21:45.

2. Bell, G.I. et al. (1986) Nucleic Acids Res. 14:7873.

3. Guvakova, M.A. (2007) Int. J. Biochem. Cell Biol. 39:890.

4. Clemmons, D.R. (2006) Curr. Opin. Pharmacol. 6:620.

5. Bluher, S. et al. (2005) Best Pract. Res. Clin. Endocrinol. Metab. 19:577.

6. Garcia-Segura, L.M. et al. (2006) Neuroendocrinology 84:275.

7. Malemud, C.J. (2007) Clin. Chim. Acta 375:10.

8. Samani, A.A. et al. (2007) Endocrine Rev. 28:20.

9. LeRoith, D. and S. Yakar (2007) Nat. Clin. Pract. Endocrinol. Metab. 3:302.

10. Denley, A. et al. (2005) Cytokine Growth Factor Rev. 16:421.

• Long Name:

  Insulin-like Growth Factor I

• Entrez Gene IDs:

  3479 (Human); 16000 (Mouse); 24482 (Rat)

• Alternate Names:

  IBP1; IGF1; IGF-1; IGF1A; IGFI; IGF-I; IGF-IA; IGF-IB; insulin-like growth factor 1 (somatomedin C); insulin-like growth factor 1; insulin-like growth factor I; insulin-like growth factor IA; insulin-like growth factor IB; Mechano growth factor; MGF; Somatomedin A; Somatomedin C; somatomedin-C