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Long-Arg3 IGF-1 (long-acting IGF-1 analog)
Research documentation
Ask sales for the IGF-1 LR3 batch COA and the analytical evidence needed to qualify the material for your study. Confirm the available purity and identity records, lot continuity, handling information, and method requirements before ordering.
Overview
IGF-1 LR3 (Long R3 IGF-1) is an 83-residue recombinant analog of native IGF-1 that reduces IGF-binding-protein (IGFBP) capture through two engineered changes working in concert. A 13-amino-acid N-terminal extension — originally an accident of an E. coli fusion-protein construct — sharply lowers IGFBP affinity, while an Arg-for-Glu substitution at position 3 further weakens that interaction. Because the resulting analog largely escapes IGFBP sequestration, it shows roughly threefold higher potency than native IGF-1 in cell-proliferation assays at matched molar concentrations, and its functional half-life is extended since IGFBP-mediated clearance no longer removes it from circulation. Lyochem supplies recombinant IGF-1 LR3 as a lyophilized reference standard to a ≥99.0% HPLC purity specification. Since this is an E. coli-expressed protein, release couples chemical-purity data (RP-HPLC) with orthogonal confirmations appropriate to a protein: SDS-PAGE and SEC for size and aggregation state, plus an optional 3T3 or MCF-7 cell-proliferation bioassay to confirm activity. Endotoxin is quantified by LAL only when included in the agreed analytical scope, because recombinant-protein processes can carry higher endotoxin than synthetic peptides. Two fill sizes (0.1 mg and 1 mg) run from cell-culture aliquots through in vivo research scales.
Applications & buyer fit
GH-axis peptides ship to research labs studying somatotropic-pathway pharmacology and related models. Ask sales for the matching batch COA. Sequence, counter-ion, or stability evidence beyond that record is included only when required by a written project scope and agreed before quotation.
Academic Laboratories
Universities, medical schools, and government research institutes qualifying a reference standard for a method-development or in vivo workflow.
Every lot has its own batch-specific CoA — HPLC purity and MS identity, plus any analytical scope agreed at quote stage — tied to the exact lot you receive.
Review a representative batch CoA before you order, so you can confirm the packet matches what your method or sponsor audit needs.
Supplied strictly as a research reagent to research institutions — not a finished dosage form and not for human administration. Buyer qualification runs at the inquiry stage.
Specifications
Documentation available on request
Regulatory note
Sold for Research Use Only under the receiving laboratory's institutional and jurisdictional regulations. Not a finished dosage form, not labelled for human administration — Lyochem's GH-axis lots are scoped to research workflows only. Buyers studying somatotropic pharmacology should specify the counter-ion form (acetate by default) and any pulse-vs-sustained study design notes at quote stage.
Selected literature
Frequently asked questions
At 83 residues IGF-1 LR3 is a small recombinant protein expressed in E. coli, so its analysis goes beyond synthetic-peptide checks. The batch COA reports RP-HPLC chemical purity and intact-mass MS identity; SDS-PAGE (apparent size) and peptide mapping are available on request. Crucially, folding and disulfide connectivity drive activity independently of chemical purity, so a cell-proliferation bioassay is recommended to confirm the material is correctly folded and biologically active. Because the E. coli host introduces endotoxin, an LAL endotoxin result is essential for in vivo work. Size, endotoxin and a functional potency readout are available on request and listed on the COA when tested, alongside the purity and mass reported for every lot.
IGF-1 LR3 aggregates readily near neutral pH on dilute reconstitution, and aggregation compromises both the monomer content that SEC measures and the activity a proliferation assay reports. Dissolving in dilute (around 0.6%) acetic acid keeps the protein in its monomeric state, preserving the species that the analytical methods were validated against. For low-concentration working stocks, adding carrier protein such as BSA limits adsorptive loss to glass and plastic that would otherwise skew concentration-controlled assays. Aliquot into single-use volumes and keep frozen; following the reconstitution buffer specified on the COA is what keeps analytical results comparable to the reference characterization.
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