IGF-1 LR3 — 1 mg (Long R3 Insulin-Like Growth Factor-1) is an 83-amino-acid analog of human IGF-1 engineered with an
Arg substitution at position 3 and a 13-residue N-terminal extension to reduce IGF-binding protein (IGFBP) interactions and enable robust IGF1R engagement in vitro.
Supplied by Peptide Tech at ≥ 99% purity (HPLC/MS verified) for
in-vitro, cellular, and biochemical research use only (RUO). Not for human or veterinary use.

Specifications

CAS Number	946870-92-4
Chemical Name	Insulin-Like Growth Factor-1, Long R3 (IGF-1 LR3)
PubChem CID	N/A (no dedicated LR3 entry)
Molecular Formula	C₄₀₀H₆₂₅N₁₁₁O₁₁₅S₉
Molecular Weight	~9.1 kDa
Sequence	83-aa IGF-1 analog with Arg3 substitution and 13-aa N-terminal extension; retains two disulfide bonds (A/B-chain–like fold)
Physical Appearance	White to off-white lyophilized powder
Container	3 mL Type I glass vial (1 mg net content)
Purity	≥ 99% (verified by HPLC & MS; third-party tested)
Solubility	Soluble in sterile water; for concentrated stocks, pre-wet with 10 mM HCl or ≤0.1% acetic acid, then dilute into final buffer. 0.22 µm filter-sterilize if required.

Molecular Structure (Reference)

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Storage & Handling

Lyophilized (unopened): Store at ≤ −20 °C, protected from light and moisture. For long-term archival, ≤ −80 °C is recommended.
After reconstitution: Aliquot into sterile, low-binding tubes; store at ≤ −80 °C. Avoid repeated freeze–thaw cycles.
Handling: Allow vial to reach room temperature before opening to minimize condensation. Use sterile technique and compatible buffers (neutral pH, add carrier protein if adsorption is a concern).
Research Use Only (RUO): Not for human or veterinary use, ingestion, diagnostic, or therapeutic applications.

Potential Applications in Research

Strictly in-vitro, cellular, or biochemical contexts — no clinical or human-use claims.

IGF1R activation studies: Map acute/sustained signaling (AKT, ERK) and ligand-specific kinetics in defined serum conditions.
IGFBP interaction controls: Benchmark reduced IGFBP binding vs. native IGF-1 to improve ligand availability in culture.
Serum-free growth/viability assays: Use as a defined IGF-axis stimulus in proliferation/survival readouts.
Receptor competition/occupancy: Compare LR3 vs. IGF-1 for binding and downstream signaling in engineered cell systems.
Processing/ECM studies: Examine how matrix or pro-IGF context modulates ligand handling at the cell surface.

Citations (PubMed)

Boomsma, J., et al. “Three-dimensional structure of human insulin-like growth factor I/II.” Biochemistry, 2002.
Pfeffer, L. A., et al. “The insulin-like growth factor (IGF)-I E-peptides modulate cell entry of the mature IGF-I protein.” Mol Biol Cell, 2009.
Chamoun, D., et al. “Regulation of granulosa cell-derived IGF-binding proteins (IGFBP-4 and IGFBP-5).” Biol Reprod, 2002.

Compliance & RUO Disclaimer

For laboratory research use only (RUO). Not a drug, food, or cosmetic. Not for human or veterinary use. Purchase and use are limited to qualified personnel operating under institutional laboratory guidelines.