Recombinant Human LR3 IGF-I/IGF-1 Protein, CF

Recombinant Human LR3 IGF-I/IGF-1 (Catalog # 8335-G1) stimulates cell proliferation in a serum-free assay using the MCF-7 human breast cancer cell line. The ED50 for this effect is 0.3-1.5 ng/mL.

1 μg/lane of Recombinant Human LR3 IGF-I/IGF-1 was resolved with SDS-PAGE under reducing (R) conditions and visualized by silver staining, showing a single band at 7 kDa.

ESI analysis of Recombinant Human LR3 IGF-I/IGF-1 (Catalog # 8335-G1). The peak at 9112 Da corresponds to the calculated molecular mass, 9118 Da.

Product Discontinued

Recombinant Human LR3 IGF-I/IGF-1 Protein, CF Summary

• Details of Functionality: 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 ED₅₀ for this effect is 0.3-1.5 ng/mL. IGFBP-3 does not inhibt its activity.
• Source: E. coli-derived human IGF-I/IGF-1 protein
  

  MFPAMPLSSLFVN	Human LR3 IGF-I/IGF-1 (Gly49-Ala118 (Glu51Arg)) Accession # P05019
  N-terminus	C-terminus

• Accession #: P05019
• N-terminal Sequence: Met-Phe-Pro-Ala-Met-Pro-Leu-Ser-Ser-Leu
• Protein/Peptide Type: Recombinant Proteins
• Gene: IGF1
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Endotoxin Note: <0.01 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Bioactivity
• Theoretical MW: 9 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 7 kDa, reducing conditions

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.
• Buffer: Lyophilized from a 0.2 μm filtered solution in phosphate buffer, pH 7.2 .
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Reconstitution Instructions: Reconstitute at 500 μg/mL in sterile PBS.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant Human LR3 IGF-I/IGF-1 Protein, CF

• 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

Background

Insulin-like Growth Factor I (IGF-I), also known as Somatomedin C, is the dominant effector of Growth Hormone (GH) and is structurally homologous to Proinsulin. Human IGF-I is synthesized as two precursor isoforms with N- and alternative 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 human IGF-I shares 94% and 96% amino acid (aa) sequence identity with the mouse and rat orthologs, respectively (2). GH stimulates the production of IGF-I in most tissues (3). Hepatocytes produce circulating IGF-I, 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 (4, 5). IGF-I regulates glucose, fatty acid, and protein metabolism, steroid hormone activity, and cartilage and bone metabolism (6-11). It plays an important role in muscle regeneration and tumor progression (1, 12, 13). IGF-I binds IGF-I R, IGF-II R, and the Insulin Receptor, although its effects are mediated primarily by IGF-I R (14). IGF-I also binds with strong affinity to IGF binding proteins (IGFBPs), which regulate the availability and biological activities of IGF-I (15, 16).

Long R3 IGF-I (LR3 IGF-I) is a 9.2 kDa synthetic analog of IGF-I that is generated by modifying the aa sequence for mature human IGF-I. These modifications include the substitution of an Arg for Glu at position 3 of the mature IGF-1 sequence and the addition of a thirteen aa N-terminal extension, which is derived from methionyl porcine Growth Hormone (17). These aa changes generate a protein that is still capable of binding to IGF-I and Insulin receptors, but shows considerably lower affinity binding to IGFBPs compared to wild-type IGF-I (17, 18). As a result, LR3 IGF-I has an increased half-life and displays increased biological potency compared to IGF-I (17-22).

1. Philippou, A. et al. (2007) In Vivo 21:45.
2. Sandberg-Nordqvist, A.C. et al. (1992) Brain Res. Mol. Brain Res. 12:275.
3. Berryman, D.E. et al. (2013) Nat. Rev. Endocrinol. 9:346.
4. Guvakova, M.A. (2007) Int. J. Biochem. Cell Biol. 39:890.
5. Sadagurski, M. and M.F. White (2013) Endocrinol. Metab. Clin. North Am. 42:127.
6. Clemmons, D.R. (2006) Curr. Opin. Pharmacol. 6:620.
7. Bluher, S. et al. (2005) Best Pract. Res. Clin. Endocrinol. Metab. 19:577.
8. Garcia-Segura, L.M. et al. (2006) Neuroendocrinology 84:275.
9. Malemud, C.J. (2007) Clin. Chim. Acta 375:10.
10. Ling, P.R. et al. (1995) Am. J. Clin. Nutr. 61:116.
11. Sheng, M.H. et al. (2014) J. Bone Metab. 21:41.
12. Samani, A.A. et al. (2007) Endocrine Rev. 28:20.
13. Gallagher, E.J. et al. (2010) Endocr. Pract. 16:864.
14. LeRoith, D. and S. Yakar (2007) Nat. Clin. Pract. Endocrinol. Metab. 3:302.
15. Denley, A. et al. (2005) Cytokine Growth Factor Rev. 16:421.
16. Duan, C. and Q. Xu (2005) Gen. Comp. Endocrinol. 142:44.
17. Francis, G.L. et al. (1992) J. Mol. Endocrinol. 8:213.
18. Voorhamme, D. and C.A. Yandell (2006) Mol. Biotechnol. 34:201.
19. Tomas, F.M. et al. (1993) Biochem. J. 291:781.
20. Tomas, F.M. et al. (1996) J. Endocrinol. 150:77.
21. Tomas, F.M. et al. (1997) J. Endocrinol. 155:377.
22. von der Thüsen, J.H. et al. (2011) Am. J. Pathol. 178:924.

Bioinformatics

• Gene Symbol: IGF1
• Uniprot:
  • P05019()