Shop IGF1-LR3 1mg

IGF-1 LR3 is produced recombinantly rather than through solid-phase chemical synthesis, reflecting its size: at 83 residues, it is considerably larger than the short synthetic peptides that make up most of this catalog.

Recombinant Production and Sequence Modifications

IGF-1 LR3's sequence differs from native IGF-1 through an arginine substitution at position 3 and a 13-residue N-terminal extension, together reducing the molecule's affinity for several IGF-binding protein (IGFBP) family members that would otherwise regulate its availability.

These modifications leave IGF-1 LR3 more available to interact directly with IGF-1 receptors in cell-based laboratory assays relative to native IGF-1, a property researchers cite as the basis for using this variant in in vitro receptor-signaling studies.

Cell-Based Differentiation Research

In vitro work using C2C12 cells, an established mouse skeletal muscle cell line, examined IGF-1 LR3's effects on differentiation index and nuclei count within this cell culture system, alongside small-molecule activin-like kinase 4/5 inhibitors tested in the same experiments.¹

Analytical Verification for a Recombinant Protein

Unlike shorter synthetic peptides verified primarily by HPLC and mass spectrometry, a full-length 83-residue recombinant protein like IGF-1 LR3 requires methods suited to larger biomolecules, including SDS-PAGE or size-exclusion chromatography to confirm molecular size and rule out aggregation.

For bulk orders, researchers are encouraged to confirm that analytical data reflects the specific expression batch supplied, since recombinant production can introduce more batch-to-batch variability than solid-phase chemical synthesis.

Storage and Handling in the Laboratory Setting

Larger recombinant proteins are more prone to surface adsorption onto labware at low concentrations, so researchers working with this peptide in cell culture assays often include a carrier protein, such as bovine serum albumin, in their experimental buffers to minimize losses.

Lyophilized storage under sub-zero freezer conditions remains standard, and a bulk shipment is generally split into a number of smaller sealed containers immediately after arrival so that only one portion at a time is subject to ambient conditions.

Comparative Research Context Among Reduced-Affinity IGF-1 Analogs

IGF-1 LR3 is one of several IGF-1 analogs engineered to reduce IGFBP binding, alongside des(1-3)IGF-1, which achieves a similar reduction through N-terminal truncation rather than extension.

Researchers comparing these analogs against native IGF-1 have used their differing IGFBP affinities to isolate IGF-1-receptor-mediated effects from the modulating influence of binding proteins in cell-based assay systems.

Important Compliance Notice

IGF-1 LR3 is intended solely for laboratory research use (in vitro) and is not approved for human, therapeutic, or diagnostic use. Any application outside controlled in vitro research environments is prohibited. These findings do not establish safety, efficacy, or suitability for any human application, and this product has not been evaluated by the FDA or any regulatory agency.

Product Information

IGF-1 LR3 is supplied as a research reagent for laboratory use only, available in bulk quantity.

References

1. Levolger S, Wiemer EAC, van Vugt JLA, et al. Inhibition of activin-like kinase 4/5 attenuates cancer cachexia-associated muscle wasting. Sci Rep. 2019;9:9826.