IGF-1 LR3
A long-acting IGF-1 analog studied in laboratory settings for cellular growth, proliferation, and tissue development
About IGF-1 LR3
IGF-1 LR3 (Insulin-like Growth Factor-1 Long R3, CAS 946870-92-4) is a modified version of human IGF-1 with an extended half-life. The 'Long' refers to a 13 amino acid extension at the N-terminus, and 'R3' indicates an arginine substitution at position 3, which reduces binding to IGF binding proteins.
IGF-1 LR3 emerged from research efforts in the late 1980s and early 1990s to create more potent versions of insulin-like growth factor. Scientists at GroPep in Adelaide, Australia, were among the first to develop this modified peptide, seeking to overcome the limitations of native IGF-1, which is rapidly bound by circulating proteins and cleared from circulation.
The key innovation was twofold: adding 13 extra amino acids to the beginning of the peptide sequence and swapping out glutamic acid for arginine at position 3. These changes dramatically reduced binding to IGF binding proteins (IGFBPs), which normally sequester and inactivate IGF-1. The result was a peptide with significantly enhanced potency and duration of action in research applications.
Since its development, IGF-1 LR3 has become widely used in cell culture research and animal studies examining growth factor biology. Its extended bioavailability makes it particularly valuable for studying IGF-1 signaling pathways without the confounding effects of binding protein interactions.
Quick Facts
| CAS Number | 946870-92-4 |
|---|---|
| Molecular Formula | C₄₀₀H₆₂₅N₁₁₁O₁₁₅S₉ |
| Molar Mass | 9111.3 g/mol |
| Sequence | 83 amino acids (LR3 extended analog) |
| Form | Lyophilized powder |
| Purity | 99%+ (HPLC verified) |
| Third-Party Testing | Freedom Diagnostics (COA included) |
| Storage | Room temp 3–4 months; refrigerate post-reconstitution |
| Price (from) | $140.00 USD |
| SKU | PF-IGF1LR3-1MG |
How IGF-1 LR3 Works
Preclinical studies have examined IGF-1 LR3's interactions with the IGF-1 receptor and downstream signaling cascades. Published investigations suggest potent activation of cellular growth pathways with reduced binding protein sequestration compared to native IGF-1.
IGF-1 Receptor Binding
IGF-1 LR3 binds to the IGF-1 receptor (IGF-1R), a receptor tyrosine kinase present on most cell types. Upon binding, the receptor undergoes autophosphorylation, initiating intracellular signaling cascades that regulate cell growth, survival, and metabolism.
PI3K/Akt Pathway Activation
Receptor activation triggers phosphorylation of insulin receptor substrates (IRS-1/2), which recruit and activate phosphoinositide 3-kinase (PI3K). This generates PIP3, leading to Akt activation and downstream effects on protein synthesis, glucose uptake, and cell survival.
MAPK/ERK Signaling
Parallel to PI3K signaling, IGF-1R activation stimulates the Ras-Raf-MEK-ERK cascade through Grb2/SOS recruitment. This MAPK pathway primarily drives cellular proliferation and differentiation responses in target tissues.
mTOR and Protein Synthesis
Akt activation leads to mTORC1 stimulation, which phosphorylates S6K1 and 4E-BP1. These downstream effectors enhance ribosomal biogenesis, cap-dependent translation initiation, and overall protein synthesis capacity.
Frequently Asked Questions
- What is IGF-1 LR3?
- IGF-1 LR3 (Insulin-like Growth Factor-1 Long R3, CAS 946870-92-4) is a modified version of human IGF-1 with an extended half-life. The 'Long' refers to a 13 amino acid extension at the N-terminus, and 'R3' indicates an arginine substitution at position 3, which reduces binding to IGF binding proteins.
- What is the CAS number for IGF-1 LR3?
- The CAS number for IGF-1 LR3 is 946870-92-4.
- What purity is Peptide Foundry's IGF-1 LR3?
- Peptide Foundry's research peptides are manufactured to 99%+ purity. Every batch is verified by an independent third-party laboratory (Freedom Diagnostics) using high-performance liquid chromatography (HPLC) for purity and identity, Limulus amebocyte lysate (LAL) assay for bacterial endotoxin, and inductively coupled plasma mass spectrometry (ICP-MS) for heavy-metal contamination. A Certificate of Analysis is published for every product and batch.
- How should IGF-1 LR3 be stored?
- Lyophilized (freeze-dried) peptides are stable at room temperature for 3–4 months. Once reconstituted with bacteriostatic water, store refrigerated (2–8 °C) and use within 30 days. Keep away from direct light and extreme temperatures.
- Does IGF-1 LR3 ship with a Certificate of Analysis?
- Yes. Every batch of every product ships with a Certificate of Analysis from Freedom Diagnostics, an independent third-party analytical laboratory. The COA documents HPLC purity, peptide identity, endotoxin testing, and heavy-metals screening.
- Is IGF-1 LR3 sold for human use?
- No. All products sold by Peptide Foundry are strictly for in-vitro research and laboratory use only (RUO). They are not intended for human or animal consumption, therapeutic use, or diagnostic application.
Scientific References
- Francis GL, et al. Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. Journal of Molecular Endocrinology. 1992;8(3):213-223. PubMed: 1378742
- Tomas FM, et al. Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. Biochemical Journal. 1992;282(Pt 1):91-97. PubMed: 1371669
- Ballard FJ, et al. Does IGF-I ever act through the insulin receptor? Cytokine & Growth Factor Reviews. 2007;18(1-2):7-12.
This product is sold strictly for in-vitro research use only (RUO). It is not intended for human or animal consumption, therapeutic use, or diagnostic application.