Catalogue / IGF-1 LR3
IGF-1 LR3
Also written as Long R3 IGF-1.
An 83 residue analogue of insulin-like growth factor 1 with an arginine substitution at position 3 and a thirteen residue N-terminal extension.
| Class | Recombinant proteins |
| Determination | Recombinant protein, content, purity and dimer |
| Price | 650 USD |
IGF-1 LR3 is identified against a certified reference standard rather than against a published mass, because commercially supplied material varies in composition between suppliers. Purity is reported separately by reversed-phase chromatography at 214 nm and describes the chromatographable fraction only.
| Three disulfide bridges must be correctly paired. Misfolded material with scrambled bridges has the identical mass and different activity, so mass confirmation alone does not establish correct folding. |
| The compound is frequently substituted with native IGF-1, which is 1,500 daltons lighter and considerably cheaper. |
| Aggregation on reconstitution is common and requires size exclusion to quantify. |
Every compound fails in its own way. A generic peptide method applied without regard to these specifics produces a number that looks like a result and is not one.
Expressed rather than synthesised. The failure modes are different: aggregation, deamidation, oxidation and truncation, none of which a single purity number captures.
RP-HPLC purity, size exclusion chromatography for dimer and higher aggregate, and where required a charge-variant separation. Aggregate is reported as a separate figure because a dimer is chemically still the same protein.
Where the delivered milligram figure matters rather than the percentage, net peptide content by combustion analysis and water by Karl Fischer are added, and the certificate carries a closed mass balance instead of a single purity number.
| LC-MS identity | Measured mass |
| RP-HPLC purity | Area at 214 nm |
| Net peptide content | Milligrams |
| Water content | Karl Fischer |
| Counter-ion | Ion chromatography |
| Bacterial endotoxins | USP <85> |
What is the molecular weight of IGF-1 LR3?
No molecular weight is published for IGF-1 LR3 on this page, because the composition of commercially supplied material varies between suppliers and an unverified figure on an analytical site is worse than an absent one. Identity is established against a certified reference standard at the time of analysis.
How is IGF-1 LR3 tested for purity and identity?
RP-HPLC purity, size exclusion chromatography for dimer and higher aggregate, and where required a charge-variant separation. Aggregate is reported as a separate figure because a dimer is chemically still the same protein. Purity describes the chromatographable fraction only and is not the same quantity as the peptide mass delivered per vial.
What goes wrong when IGF-1 LR3 is analysed?
Three disulfide bridges must be correctly paired. Misfolded material with scrambled bridges has the identical mass and different activity, so mass confirmation alone does not establish correct folding.
What does IGF-1 LR3 analysis cost at ANALYTON?
Recombinant protein, content, purity and dimer is priced at 650 US dollars, covering the determinations described on this page. Content, safety and elemental determinations are ordered alongside and are priced separately on the price list.
Other compounds in this class
Updated 2026-09-01. Masses computed at build, not transcribed.