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Recombinant human IGF-1 LR3 protein (Qk041)
Human insulin-like growth factor 1 long arginine 3 (IGF-1 LR3) 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. IGF-1 LR3 can be used for the consistent, reproducible maintenance of human pluripotent stem cells.
Qkine IGF-1 LR3 is a highly pure and bioactive 9 kDa protein monomer, animal origin-free (AOF) and carrier-protein free (CF).
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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For any questions, please email orders@qkine.com
Summary
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 origin-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
Cell culture media optimisation and replacement of insulin in defined media
human
porcine (pig)
bovine (cow)
Bioactivity
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
Purity
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.
Qkine IGF-1 LR3 is stable and bioactive in conditioned media for 7 days
A
B
Stability and bioactivity of Qkine IGF-1 LR3 (Qk041). SDS-PAGE of recombinant IGF-1 LR3 (A), protein was not degraded when incubated in HEK293T conditioned media for 7 days. Bioactivity was determined using the IGF-1 LR3-responsive firefly luciferase reporter assay (B). Transfected HEK293T cells were treated in triplicate for 4 hours with a serial dilution of IGF-1 LR3 which had been pre-incubated in conditioned media for 2 or 7 days. Firefly luciferase activity was measured and normalised to the control Renilla luciferase activity.
Protein background
The insulin-like growth factors (IGFs) are a family of proteins with a similar structure to insulin. IGF-1 has an A and B chain connected by disulphide bonds, its similarity to insulin means it can bind with low affinity to the insulin receptor [1]. 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 [1]. IGF-1 exerts its biological effect through binding to the IGF1 receptor (IGF1R), its effect is modulated through interaction with a group of binding proteins (IGFBPs), which tend to inhibit the effect of IGF-1 [2]. Through IGF1R the Ras-MAPK and PI3 kinase signaling pathways are activated leading to increased cell proliferation and survival [2].
IGF-1 can be used to support maintenance of human embryonic stem cell (ESC) [3] and mesenchymal stem cell (MSC) cultures [3, 4].
Insulin-like growth factor long arginine 3 (IGF-1 LR3), is a widely used synthetic analog of IGF-1 with an arginine replacing glutamic acid at position 3 (arginine 3, R3), and an additional 13 amino acids at its N-terminus (long, L). 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 [5].
Additional resources
FAQ
IGF-1 LR3 is a modified form of IGF-1, it is more potent and stable than unmodified IGF-1.
IGF-1 LR3 is a synthetic protein.
IGF-1 LR3 has an arginine instead of a glutamic acid at the third position in its amino acid sequence and an additional 13 amino acids at its N-terminus. IGF-1 LR3 remains an agonist of the IGF-1 receptor, but it has very low affinity for IGFBPs, which inhibit IGF-1, making it more potent. IGF-1 LR3 also has a significantly longer half-life than IGF-1.
IGF-1 LR3 binds to the IGF-1 receptor (IGF1R).
IGF1R is linked to various cytoplasmic second messenger molecules including the RAS-MAPK and PI3K signaling networks.
IGF-1 LR3 can be used to replace IGF-1 in stem cell cultures. Increased potency and stability means less IGF-1 LR3 is needed compared to unmodified IGF-1.
Our products are for research use only and not for diagnostic or therapeutic use. Products are not for resale.
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