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IGF-1 LR3

IGF-1 LR3, or Long-R3-IGF-1, is a recombinant/synthetic analog of human insulin-like growth factor 1 (IGF-1) used as a reference material in analytical and cell-signaling research.

CAS 143045-27-6UniProt P05019Type ProteinResearch Use Only · reference

Representative structure of native IGF-1 (PDB 1GZR); IGF-1 LR3 differs by a 13-residue N-terminal extension and an Arg3 substitution, not depicted.

Identity & structure

Amino-acid sequence · 83 aa

MFPAMPLSSLFVNGPRTLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA

N-terminal extension (the “Long”): MFPAMPLSSLFVN
Arg3 substitution (the “R3”): Glu→Arg at mature position 3

83-residue single chain: the 13-residue N-terminal extension MFPAMPLSSLFVN (the “Long”) precedes the 70-residue mature human IGF-1 sequence, which carries the Glu3→Arg3 substitution (the “R3”). Six cysteines pair into three intramolecular disulfide bonds, as in native IGF-1.

IGF-1 LR3 — identity and specification
Identity
Type	Protein
Also known as	Long R3 IGF-1, Long-R3-IGF-I, LR3-IGF-1, LR3 IGF-I, IGF-1 Long R3, IGF1 LR3, Long Arg3 IGF-1, Receptor-grade LR3-IGF-I, Long R3 IGF-I recombinant analog
CAS	143045-27-6
PubChem CID	Not assigned — a protein of this size receives no small-molecule PubChem CID
UniProt	P05019 — parent — human IGF-1; the analog is a modified derivative, not the native entry
Research class	Secretagogue & Regulatory
Structure
Length	83 aa
Molecular formula	C400H619N111O115S9
InChIKey	Not assigned — proteins are outside InChI’s practical domain
PDB (proxy)	1GZR
Analytical
Average molecular weight	9,111.5 Da (average, folded — three disulfide bonds)

Folded form (three disulfide bonds; −6 H). The fully reduced chain is C400H625N111O115S9, average 9,117.6 Da — databases quoting ~9,117.6 Da list the reduced species.

IGF-1 LR3 is a single 83-residue chain: the 13-residue N-terminal extension MFPAMPLSSLFVN precedes the 70-residue mature IGF-1 sequence, which carries the Glu3→Arg3 substitution. Six cysteines pair into three intramolecular disulfide bonds. As a defined, non-glycosylated covalent species it has a legitimate molecular formula (C400H619N111O115S9, folded) and average mass (9,111.5 Da); the reduced chain is C400H625N111O115S9 (9,117.6 Da).

Reference context

IGF-1 LR3, or Long-R3-IGF-1, is a recombinant/synthetic analog of human insulin-like growth factor 1 (IGF-1) used as a reference material in analytical and cell-signaling research. It is not native IGF-1: the 70-residue mature human IGF-1 sequence (derived from UniProt P05019) is modified in two defined ways — the glutamate at position 3 is replaced by arginine (Glu3→Arg3, the “R3”), and a 13-residue N-terminal peptide extension (MFPAMPLSSLFVN, the “Long”) is fused to the amino terminus — giving a single 83-residue chain. The molecule retains the three intramolecular disulfide bonds and six cysteines of native IGF-1, and its calculated average mass is approximately 9,111 Da in the folded (disulfide-bonded) state (about 9,117.6 Da for the reduced chain). Because it is a defined, non-glycosylated covalent species, a molecular formula (C400H619N111O115S9, folded) and a CAS number (143045-27-6) can both be assigned — a point of contrast with the larger glycoproteins in this reference set. Lineará lists IGF-1 LR3 as a characterization-only reference entity. For Research Use Only — Not for Human or Veterinary Use.

Listed solely as a characterized analytical reference — no representation is made as to any biological effect. For Research Use Only — not for human or veterinary use.

How IGF-1 LR3 is characterized

For a folded protein, identity rests on the amino-acid sequence and its cross-references rather than a small-molecule structure. The sequence above is the anchor identifier; the UniProt accession and the representative Protein Data Bank entries locate the fold. As a defined, non-glycosylated covalent species it carries a legitimate molecular formula and average mass, computed from the verified sequence and reconciled with the reported figures.

IdentityAmino-acid sequence · UniProt P05019

StructurePDB ribbon (proxy) · 1GZR

MassAverage MW · from formula

Computed mass & m/z →How an HPLC trace is read →

Frequently asked questions

What is IGF-1 LR3?

IGF-1 LR3 (Long-R3-IGF-1) is an 83-residue analog of human insulin-like growth factor 1 in which glutamate 3 is replaced by arginine and a 13-residue peptide is fused to the N-terminus. It is a single-chain protein, not a native hormone and not a short peptide.

How does IGF-1 LR3 differ from native IGF-1?

Native mature IGF-1 is 70 residues; IGF-1 LR3 is 83 residues. The two structural differences are the Glu3→Arg3 substitution and the 13-residue N-terminal extension (MFPAMPLSSLFVN). Both molecules keep the same six cysteines and three disulfide bonds.

What is the molecular weight of IGF-1 LR3?

Its calculated average mass is about 9,111 Da in the folded, disulfide-bonded state, or about 9,117.6 Da for the fully reduced chain — the roughly 6 Da difference is the six hydrogens lost when the three disulfide bonds form.

Does IGF-1 LR3 have a molecular formula and CAS number?

Yes. Because it is a single defined, non-glycosylated protein species, it can be assigned a molecular formula (C400H619N111O115S9 for the folded form) and the CAS Registry Number 143045-27-6.

Does IGF-1 LR3 have a PubChem CID or InChIKey?

No. Proteins of this size are not assigned small-molecule PubChem Compound IDs or InChIKeys; the appropriate identifiers are its amino-acid sequence, its parent UniProt entry (P05019), and its CAS number.

Is IGF-1 LR3 a peptide?

Not exactly. IGF-1 LR3 is a protein — a larger polypeptide of 83 residues. It is built from amino acids like a peptide, but is longer and adopts a defined folded structure.

How is IGF-1 LR3 stored and reconstituted?

As a research material, IGF-1 LR3 is typically handled as a lyophilized (freeze-dried) powder. It is kept desiccated and cold — commonly 2–8 °C for short periods and −20 °C for longer storage — and reconstituted in sterile or bacteriostatic water. This is storage and handling information only, not a use protocol.

Does Lineará sell IGF-1 LR3?

No. IGF-1 LR3 is listed here only as a characterization reference entity. It is not part of the Lineará formulary, has no price or certificate of analysis, and is not offered for sale.

Is IGF-1 LR3 approved for human use?

No. IGF-1 LR3 is presented strictly as characterization reference data. It is not a drug, is not approved for any human or veterinary use, and must not be administered to humans or animals.

References

UniProt — protein sequence & annotation (P05019). UniProt →
RCSB Protein Data Bank — representative structure (1GZR).
CAS Registry Number 143045-27-6.

Research professionals only

Reference data

This monograph is characterization reference data. Lineará does not sell, stock, or certify IGF-1 LR3.

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áFor Research Use Only · Not for human or veterinary use · Not for diagnostic or therapeutic use