IGF-1 LR3 (Insulin-Like Growth Factor-1 Long R3) is a synthetic analog of IGF-1 with an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications significantly extend its biological half-life from approximately 10 minutes (native IGF-1) to 20–30 hours, making it a valuable tool in cellular proliferation and differentiation research.
Chemical Profile
| CAS Number | 946870-92-4 |
|---|---|
| Molecular Weight | 9,111.0 g/mol |
| Amino Acids | 83 (70 IGF-1 + 13 N-terminal) |
| Key Modification | R3 substitution + 13-aa extension |
| Appearance | Lyophilized white powder |
| Purity (Aurex) | ≥99% (HPLC) |
The LR3 Modification
Native IGF-1 has a very short half-life due to rapid binding with IGF-binding proteins (IGFBPs) in serum. The LR3 modification works through two mechanisms: (1) The arginine at position 3 reduces binding affinity to IGFBPs by approximately 1,000-fold, and (2) the 13-amino acid N-terminal extension further sterically hinders IGFBP interaction. The result is a molecule that remains free in circulation much longer, increasing bioavailability in research models.
Research Applications
- Myoblast proliferation and skeletal muscle cell growth studies
- Neuronal differentiation and neuroprotection research
- Osteoblast proliferation and bone mineralization studies
- IGF-1 receptor (IGF1R) signaling pathway research
- Cell survival and anti-apoptotic mechanism studies
- Satellite cell activation and muscle regeneration models
Storage Considerations
IGF-1 LR3 requires careful storage due to its large molecular weight and complexity. Store lyophilized at -20°C. When reconstituting, use acetic acid (AA) buffer or the buffer recommended for your specific assay. Standard bacteriostatic water is acceptable for general reconstitution. Once in solution, refrigerate at 2–8°C and use within 1–2 weeks.