IGF-1 LR3 Peptide

IGF-1 LR3, or Long R3 insulin-like growth factor 1, is an 83-residue recombinant analogue of human IGF-1. Two engineered changes define it: arginine replaces glutamate at position 3, and a 13-amino-acid extension is added to the N-terminus. Together these raise the molecular weight to roughly 9118 g/mol and, more importantly, sharply reduce affinity for the IGF binding proteins that normally sequester more than 95% of circulating IGF-1.

Vials are filled at 0.1 mg and 1 mg, small by the standards of this catalogue, because the analogue is used at nanomolar concentrations in culture and a milligram covers a great many plates. At 9117.60 g/mol, 1 mg is about 110 nanomoles, so reconstituting into 1 mL gives a stock near 110 micromolar that is then diluted several thousand-fold. At those working concentrations adsorption onto plastic tubes and tips becomes a measurable loss, which is why dilute stocks are normally carried in a carrier protein such as 0.1% bovine serum albumin. Published use sits mostly in serum-free and reduced-serum culture, myoblast and other proliferation assays, and IGF-1 receptor signalling work where binding-protein interference from serum would otherwise confound the readout.

IGF-1 LR3 ships as a lyophilized powder, so nothing on this page can state a concentration: the figure you work with is the one you create when you add diluent. Put the vial mass and the volume you intend to use into the peptide reconstitution calculator and it returns mg/mL, mcg/mL and the mass sitting at each mark on a U-100 syringe.