IGF-1 LR3
A 83-residue synthetic analogue of insulin-like growth factor 1, modified with a 13-residue N-terminal extension and Arg³ substitution to reduce IGF-binding protein (IGFBP) affinity ~2–3x and extend bioavailability in animal models. Standard reference compound for IGF-1R signaling and anabolic pathway research.
Free COA included · Free shipment protection · 99%+ purity by HPLC & MS · Lyophilized powder
Certificate of Analysis — Included Free
Every batch independently tested by U.S.-accredited labs. Lot-matched COA confirms identity, purity ≥99% by HPLC, and safety screening.
Research Overview
IGF-1 LR3 (Long R3 Insulin-Like Growth Factor-1) is a synthetic 83-amino acid analogue of human IGF-1, constructed by adding a 13-residue N-terminal extension (Gly-Pro-Glu-Thr-Leu-Cys-Gly-Ala-Glu-Leu-Val-Asp-Ala-Leu-Gln-Phe-Val-Cys-Gly-Asp-Arg) and substituting arginine at position 3 in the mature IGF-1 sequence. These modifications reduce its affinity for IGF-binding proteins (IGFBP-1 through IGFBP-6) by approximately 2-to-3-fold compared to native IGF-1, while retaining full receptor binding potency at the IGF-1 receptor (IGF-1R).
In vitro research using IGF-1R-expressing cell lines has characterized LR3's receptor binding kinetics, activation of AKT and MAPK signaling pathways, and effects on cell proliferation, survival, and glucose uptake compared to native IGF-1. The reduced IGFBP binding makes it a valuable research tool for studying IGF-1R signaling in cell culture without the confounding effects of endogenous binding proteins in serum-containing media.
Protein biochemistry research has used IGF-1 LR3 extensively in cell culture media optimization, as its extended activity permits experiments with lower exogenous concentrations. Structural studies have used it as a reference ligand for IGF-1R crystallography and cryo-EM experiments.
All referenced studies are preclinical or in vitro. Not for human use.
Molecular Information
| Full Name / IUPAC | IGF-1 LR3 |
| CAS Number | 112603-57-3 |
| Molecular Formula | C₄₀₀H₆₂₅N₁₁₁O₁₁₅S₉ |
| Molecular Weight | 9,111.5 g/mol |
| Sequence / Structure | 83-aa; N-terminal 13-aa extension + Arg³ substitution in IGF-1 core |
| Appearance | White lyophilized powder |
| Solubility | Soluble in 0.1 M HCl or acetic acid; dilute to working concentration in PBS |
| Format | Lyophilized (freeze-dried) powder |
| SKU | CL-030 |
Quality & Testing
- Purity: ≥99% by HPLC
- Identity: Confirmed by Mass Spectrometry (LC-MS)
- Heavy Metals: Screened; below detection thresholds
- Endotoxin: Tested per LAL assay
- Lot Tracking: Lot number on every vial matches published COA
- Packaging: Nitrogen-purged, sealed glass vials
Storage & Handling
- Short-term: Room temperature (15–25°C), dry, dark — up to 4 weeks
- Long-term: Refrigerated at 2–8°C — up to 18 months lyophilized
- Extended: −20°C; avoid freeze-thaw cycling
- Store at −20°C. Reconstitute in 0.1 M HCl then dilute in PBS; stable 30 days at 4°C. Carrier protein (BSA 0.1%) may be added for dilute solutions.
This compound is supplied for in vitro research and laboratory use only. It is not for human or veterinary use, is not a drug or dietary supplement, and has not been evaluated or approved by the FDA or any regulatory agency for any therapeutic application. Purchasers must be 18 years of age or older and qualified researchers operating in compliance with all applicable local, state, and federal regulations governing research chemicals.
