Molecular data
| Molecular formula | C400H625N111O115S9 |
|---|---|
| Molecular weight | 9117.6 Da |
| Sequence | 83 amino acids — human IGF-1(1-70) plus 13-residue N-terminal extension; Arg3 substitution |
| Sequence length | 83 residues |
| CAS / identifier | 946870-92-4 |
| Physical form | Lyophilized powder |
| Available sizes | 1mg |
How it works
Insulin-Like Growth Factor Receptor Activation
IGF-1 LR3 (Long R3 IGF-1) is an 83-amino-acid analog of human IGF-1, carrying a 13-residue N-terminal extension and an arginine-for-glutamate substitution at position 3. It binds and activates the type 1 IGF receptor (IGF-1R), a receptor tyrosine kinase, triggering downstream PI3K/Akt and MAPK/ERK signaling.
- Retains near-native affinity for IGF-1R
- Activates PI3K/Akt/mTOR protein-synthesis signaling
- Engages MAPK/ERK proliferation pathways
Extended Bioavailability
The N-terminal extension and Arg3 substitution lower the analog's affinity for IGF-binding proteins (IGFBPs) by roughly 100- to 1,000-fold relative to native IGF-1. With less of the molecule sequestered by IGFBPs, more remains free to engage IGF-1R, giving a markedly longer functional half-life in culture systems.
- ~100–1,000× lower IGFBP affinity
- Greater free fraction available to the receptor
- Longer-lasting signaling than native IGF-1
Protein Synthesis & Cell Survival
Through Akt activation, IGF-1 signalling engages mTOR/p70S6K-driven protein synthesis, GSK3β and FoxO-mediated protein degradation — a cascade extensively characterised in skeletal-muscle and cell-culture research models.
- Activates mTOR–p70S6K translation
- Inhibits proteasomal/FoxO degradation
- Anti-apoptotic cell survival measured
What the research shows
Serum-Free Cell Culture
Long R3 IGF-1 sustains growth, viability and recombinant-protein productivity of serum-free CHO cell lines, outperforming insulin under production conditions.
Potency vs Insulin in Culture
In serum-free HEK293 culture, LONG R3 IGF-I acts as a more potent growth and survival factor than insulin or native IGF-I, effective at far lower concentrations.
Myotube Hypertrophy Pathways
IGF-1 drives skeletal myotube hypertrophy via PI(3)K/Akt/mTOR and PI(3)K/Akt/GSK3 signaling — a foundational model for anabolic growth research.
IGF1–Akt/PKB Regulation
The IGF1-Akt/PKB axis controls skeletal-muscle protein synthesis and degradation, as established across transgenic and knockout genetic models.
Specification
| Chemical Name | Long R3 Insulin-Like Growth Factor-1 (IGF-1 LR3) |
|---|---|
| Sequence | 83 amino acids — human IGF-1(1-70) plus 13-residue N-terminal extension; Arg³ |
| Molecular Weight | 9,117.6 Da |
| Molecular Formula | C₄₀₀H₆₂₅N₁₁₁O₁₁₅S₉ |
| CAS Number | 946870-92-4 |
| Form | Lyophilized powder |
| Purity | ≥99% (HPLC verified) |
| Testing | Third-party HPLC, Mass Spec, Endotoxin |
| Storage | -20°C for long-term stability |
| Solubility | Sterile acidified water or bacteriostatic water |
| COA | Included with every order |
Frequently asked questions
What is IGF-1 LR3 and how does it differ from native IGF-1?
IGF-1 LR3 (Long R3 IGF-1) is an engineered 83-amino-acid analog of human insulin-like growth factor 1. It adds a 13-residue N-terminal peptide extension and replaces the glutamic acid at position 3 with arginine. These changes substantially reduce binding to IGF-binding proteins (IGFBPs) while preserving affinity for the IGF-1 receptor, so it stays active longer than native IGF-1 in culture.
Why is IGF-1 LR3 used in cell culture?
Because it resists IGFBP sequestration and signals potently through IGF-1R, IGF-1 LR3 is a widely used serum-free media supplement. Studies show it supports growth, viability and recombinant-protein productivity of CHO and HEK293 cell lines at concentrations far below those required for insulin.
What signaling pathways does IGF-1 LR3 activate?
By activating the IGF-1 receptor tyrosine kinase, it engages the PI3K/Akt/mTOR pathway (protein synthesis and cell survival) and the MAPK/ERK pathway (proliferation). In skeletal-muscle models, the IGF1-Akt axis also suppresses protein degradation via FoxO and GSK3β.
How should IGF-1 LR3 be stored?
Store the lyophilized powder at -20°C, protected from moisture and light. Avoid repeated freeze–thaw cycles to preserve activity.
Is this product intended for human use?
No. Research-grade IGF-1 LR3 sold here is strictly for in vitro laboratory research and analytical applications. It is not a drug and is not intended for human or veterinary use, consumption, or any clinical application.
For laboratory research use only. Not a drug, supplement, or medical product; not for human or animal use. All findings referenced are from published preclinical/laboratory research.