IGF-1LR3

IGF-1 LR3 is an 83-residue recombinant IGF-I analogue with an amino-terminal extension and an Arg3 substitution.

Research overview

IGF-1 LR3 belongs to the recombinant Long IGF-I analogue series. The original study describes an amino-terminal extension containing a methionyl porcine growth-hormone segment followed by Val-Asn, together with replacement of Glu3 in the IGF-I region by arginine. These changes distinguish Long [Arg3]-IGF-I from Long IGF-I and Long [Gly3]-IGF-I. Investigators expressed the constructs in Escherichia coli and examined the folding of their protein chains. They then compared receptor association and interactions with IGF-binding proteins using several cellular systems. The reported models included rat L6 myoblasts, H35 hepatoma cells and chicken embryo fibroblasts, which differed in their receptor and binding-protein context [1].

A later expression study examined IGF-I and LR3 IGF-I in Pichia pastoris, using xylanase as a fusion partner. Its focus was recombinant expression, recovery of the proteins and cell-based characterization. The xylanase-containing expression construct is a distinct experimental intermediate and should not be mistaken for the final LR3 analogue. The two papers thus address different questions: the first compares related sequences and protein associations, while the second examines an expression platform. Neither a parent-protein database accession nor the name of an expression fusion fully specifies a particular laboratory preparation. Sequence, folding and construct boundaries remain separate parts of the experimental identity [2].

Laboratory storage and handling

Keep the sealed vial cold, dry and protected from light, following the conditions in the documentation supplied with the lot. Let the vial reach room temperature before opening to limit moisture condensation. Avoid repeated freezing and thawing of laboratory stocks. Record the lot identifier and the material form with each experiment, and use standard laboratory protective equipment.

Questions about IGF-1 LR3

References

1. Novel recombinant fusion protein analogues of insulin-like growth factor (IGF)-I indicate the relative importance of IGF-binding protein and receptor binding for enhanced biological potency. J Mol Endocrinol 1992. PMID 1378742
2. Recombinant expression of IGF-1 and LR3 IGF-1 fused with xylanase in Pichia pastoris. Appl Microbiol Biotechnol 2023. PMID 37261455

Identity data checked on 2026-10-03. Literature summaries describe published research models and are not specifications of any product lot.