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Recombinant human/bovine/porcine IGF-1 LR3 protein (Qk041)

Human IGF-1 LR3, insulin-like growth factor long arginine 3, protein is a synthetic analog of IGF-1. The substitutions include an Arginine substitution and an N-terminal protein extension. Consequently, IGF-1 LR3 has improved biological potency and extended half-life.

Highly pure and bioactive 9 kDa IGF-1 LR3 protein monomer, animal-free (AF) and carrier-protein free (CF). IGF-1 LR3 is often used in the maintenance of human pluripotent stem cells [1].

Orders are typically shipped same or next day (except Friday).
Easy world-wide ordering, direct or through our distributors.

1000µg will be despatched as 2 x 500µg

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  • High purity human IGF-1 LR3 protein (Uniprot:P05019 for IGF-1 wild-type protein)

  • >98%, by SDS-PAGE quantitative densitometry

  • 9 kDa

  • Expressed in E. coli. 

  • Animal-free (AOF) and carrier protein-free.

  • Manufactured in our Cambridge, UK laboratories

  • Lyophilized from acetonitrile, TFA

  • Resuspend in water at >100 µg/ml, prepare single use aliquots, add carrier protein if desired and store frozen at -20°C or -80°C

Featured applications

Long R3 IGF-I, Insulin-like Growth Factor-I, Somatamedin C, IGF-IA

1. Wang, Linlin, et al. ‘Self-Renewal of Human Embryonic Stem Cells Requires Insulin-like Growth Factor-1 Receptor and ERBB2 Receptor Signaling’. Blood, vol. 110, no. 12, Dec. 2007, pp. 4111–19.

2. Laron, Z. ‘Insulin-like Growth Factor 1 (IGF-1): A Growth Hormone’. Molecular Pathology, vol. 54, no. 5, Oct. 2001, pp. 311–16.

3. Tomas, F. M., et al. ‘Insulin-like Growth Factor-I (IGF-I) and Especially IGF-I Variants Are Anabolic in Dexamethasone-Treated Rats.’ Biochemical Journal, vol. 282, no. Pt 1, Feb. 1992, pp. 91–97.

porcine (pig)
bovine (cow)


IGF-1 LR3 bioactivity graph

IGF-1 LR3 activity is determined using the Promega serum response element luciferase reporter assay (*) in transfected MCF-7 cells. Cells are treated in triplicate with a serial dilution of IGF-1 LR3 for 4 hours. Firefly luciferase activity is measured and normalized to the control Renilla luciferase activity.

EC50 = 1.3 nM (11.7 ng/mL).

Data from Qk041 lot #104315.

*Promega pGL4.33[luc2P/SRE/Hygro] #E1340


IGF-1 LR3 bioactivity graph

IGF-1 LR3 migrates as a single band at 10 kDa in non-reducing (NR) conditions and upon reduction (R).  No contaminating protein bands are visible.

Purified recombinant protein (3 µg) was resolved using 18% w/v SDS-PAGE in reduced (+β-mercaptothanol, R) and non-reduced (NR) conditions and stained with Coomassie Brilliant Blue R250.  Data from Qk041 batch #104315.

Further quality assays

  • Mass spectrometry: single species with expected mass

  • Analytical reversed-phase: single sharp peak 

  • Endotoxin: <0.005 EU/μg protein (below level of detection)

  • Recovery from stock vial >95%

We are a company founded and run by scientists to support innovation in stem cell biology and regenerative medicine.  To enhance reliability and reproducibility in your applications, all our products are exceptionally high purity, with complete characterisation and bioactivity analysis on every lot.

Protein background

Insulin-like growth factor 1 (IGF-1) is a protein with a similar structure to insulin and is used frequently to replace or reduce the requirement for insulin in cell culture media.  IGF-1 is a primary mediator of growth hormone (GH), with growth-promoting effects on most cells and tissues including skeletal muscle, cartilage, bone, liver, kidney, nerve, skin, hematopoietic, and lung [2].

IGF-1 LR3, insulin-like growth factor long arginine 3, is a widely used synthetic analog of IGF-1.  IGF-1 LR3 has an arginine replacing glutamic acid at position 3 (arginine 3, R3), and an additional 13 amino acids at its N-terminus (long, L) (this aa sequence is derived from methionyl porcine Growth Hormone). IGF-1 LR3 retains the ability to bind IGF-1 and insulin receptors but has reduced binding affinity to insulin-like growth factor-binding proteins (IGFBPs). Consequently, IGF-1 LR3 has improved potency and metabolic stability (the half-life of IGF-1 LR3 is approximately double that of IGF-1) [3].

Our products are for research use only and not for diagnostic or therapeutic use.  Products are not for resale.

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