IGF1-LR3

IGF1-LR3 is a recombinant 83-amino-acid analogue of native IGF-1 (70 AA) featuring two structural modifications: an N-terminal 13-residue extension (MFPAMPLLSLFVN) and substitution of glutamic acid at position 3 with arginine (Arg3). These changes reduce IGFBP-1 through IGFBP-6 binding affinity by approximately 1,000-fold relative to native IGF-1, effectively eliminating IGFBP sequestration and increasing the proportion of free, biologically active peptide in experimental systems. Full IGF-1R agonist activity is preserved, with downstream activation of PI3K/Akt, MAPK/ERK, and mTOR signalling cascades. Plasma half-life extends to approximately 56–72 hours versus approximately 10–20 minutes for native IGF-1. Researchers use IGF-1 LR3 to investigate IGF-1R signalling in sustained-activation contexts, anabolic pathway regulation, and the consequences of IGFBP-uncoupled IGF-1R engagement on cell proliferation, differentiation, and metabolic substrate utilisation.