We report net peptide content, not just purity — so the milligrams you dose aren't padded with water and counter-ion. RP-HPLC purity and ESI-MS identity, on a lot-numbered COA.
Net peptide content, not just purity — RP-HPLC + ESI-MS, lot-numbered COA.
Net peptide content on every lot's COA.
Reading a Peptide HPLC Trace — A 5-Minute Field Guide for Bench Scientists. Read our briefing →
Reading a peptide HPLC trace — a field guide. Read →
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Long-Arg3 IGF-1 (long-acting IGF-1 analog)
Lyochem primary owner
This Lyochem page is the primary SEO owner for research labs, CROs, and method-development teams qualifying IGF-1 LR3 as a documented research-standard lot. The page should answer whether the buyer can review HPLC purity, identity confirmation, lot continuity, stability handling, and assay-fit documentation 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 at ≥99.0% HPLC purity. 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 on every lot by default, because recombinant-protein processes can carry higher endotoxin than synthetic peptides. Three fill sizes (100 mcg, 1 mg, 2 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, IGF-axis signalling, and pulse vs. sustained-elevation GH biology. Buyers qualifying a new source typically request sequence verification on the first lot, the counter-ion form (acetate by default), and stability data at −20 °C. Blends — the CJC-1295 + Ipamorelin co-formulated lot is the canonical example — are co-lyophilised rather than solution-mixed so the ratio is locked at the lyophilisation step.
Academic Laboratories
Universities, medical schools, and government research institutes qualifying a reference standard for a method-development or in vivo workflow.
Every release ships with its own batch-specific CoA — identity, purity, and the 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 analytical packet goes beyond synthetic-peptide checks. RP-HPLC establishes chemical purity, SDS-PAGE confirms apparent size, and intact-mass MS or peptide mapping anchors identity. 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. A complete reference-lot COA therefore reports purity, size, mass, endotoxin, and a functional potency readout together.
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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