Description
PrymaLab · Research use only
IGF-DES 2mg
Des(1-3)IGF-1, human IGF-1 without Gly-Pro-Glu, freeze-dried in a 2 mg vial
IGF-1 DES, written des(1-3)IGF-1, is human insulin-like growth factor 1 with its first three residues, Gly-Pro-Glu, removed, leaving a 67-residue protein held in shape by three disulfides. This listing is a sealed vial of 2 mg of the protein as freeze-dried powder. The truncated form was first found in bovine colostrum, and studies of it have examined why it is more potent than IGF-1 in cultured myoblasts and how it behaves in rats.
Specifications
| Property | Value |
|---|---|
| Compound | IGF-1 DES(1-3) Des(1-3)-IGF-1; recombinant human IGF-1 lacking the N-terminal Gly-Pro-Glu |
| CAS number | 112603-35-7 |
| Molecular formula | C 319 H 501 N 91 O 96 S 7 (reduced-chain calculation) |
| Theoretical mass | 7371.5 Da (reduced-chain calculation; 7365.4 Da with the three disulfides formed) |
| Sequence / structure | H-TLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA-OH (67 residues; three intrachain disulfides; free N- and C-termini) |
| Label claim | 2 mg/vial |
| Form | Lyophilized (freeze-dried) powder or cake in a sealed glass vial with a rubber stopper and aluminium crimp cap |
| Storage, sealed | −20 °C, desiccated, dark; avoid freeze–thaw |
| Purity specification | 99.0% or higher by RP-HPLC |
| Lot certificate | Results for the lot now shipping are in the certificate panel on this page |
| Safety data sheet | PL-SDS-084 |
Sequence and masses on the certificate
The certificate sequence begins TLCGAEL, at threonine 4 of native IGF-1, and runs 67 residues to the C-terminal alanine, with three intrachain disulfides and free ends. Two theoretical masses are listed: 7371.5 Da for the reduced chain and 7365.4 Da with all three disulfides formed, the difference being the hydrogen lost as each bond closes. The formula C319H501N91O96S7 belongs to the reduced form, and CAS 112603-35-7 identifies the truncated protein. At 7365.4 Da the 2 mg fill is about 0.27 µmol, slightly less once the water content on the certificate is allowed for. The same protein is available in solution as a preloaded IGF-1 DES pen and an IGF-1 DES nasal spray.
What the research covers
A truncated IGF-I found in nature
Des(1-3)IGF-I was isolated before it was made deliberately. Francis and colleagues purified IGF-1, IGF-2 and a truncated IGF-1 from bovine colostrum and sequenced all three1. Bovine IGF-1 proved identical to the human protein, and the variant lacked the N-terminal tripeptide Gly-Pro-Glu1. In L6 rat myoblasts the truncated form ranked first of the three at stimulating protein synthesis and inhibiting protein breakdown, and the authors called the roughly tenfold effect of removing three residues unexpected1. A truncated IGF-1 lacking the same tripeptide has also been found in human brain2.
Why it is more potent
Ballard and colleagues found destripeptide IGF-1 about seven times as potent as IGF-1 in a protein synthesis bioassay, with the same result for colostrum-derived and chemically synthesised material, yet it was no better at competing for IGF-1 binding to L6 myoblasts3. Bagley and colleagues then synthesised IGF-1 lacking one to five N-terminal residues4. Des(1-3) was the most potent in the protein synthesis assay, while competition for the receptor at 3 °C changed little until four or five residues were removed4. At 25 °C, however, the myoblasts secreted a binding protein that recognised IGF-1 and its one- and two-residue truncations at least 60-fold better than the three shorter forms4. Removing a fifth residue cut activity sharply, so the effect depends on exactly where the chain starts4.
Behaviour in rats
The binding-protein difference also showed up in whole animals. In rat plasma, labelled des(1-3)IGF-I formed almost no complexes with binding proteins, unlike IGF-I and IGF-II, and when the tracers were given intravenously most of it stayed free5. It was cleared from plasma nearly four times as fast as IGF-I, 4.59 against 1.20 ml/min per kg, and had a larger volume of distribution5. In streptozotocin-diabetic rats, a 7-day infusion study found that des(1-3)IGF-I produced about 70% of the gain in body weight and nitrogen retention seen with insulin, a level IGF-I reached only at a higher rate6. Unlike insulin, the IGF peptides did not reduce glucosuria or increase carcass fat6.
What is not established
The evidence comes from bovine colostrum, rat cell lines and rats, mostly published between 1987 and 1991, with Ballard, Francis and Tomas recurring among the authors; none of it involved people. The tripeptide that des(1-3)IGF-I lacks has a literature of its own: Sara and colleagues found that synthetic Gly-Pro-Glu inhibited glutamate binding to the NMDA receptor and stimulated acetylcholine release from rat cortical slices2. Those findings concern GPE, which this product does not contain. The IGF-1 LR3 guide compares the two IGF-1 analogues PrymaLab sells.
How each lot is tested
Every lot is tested in PrymaLab’s own laboratory in Ashland, Kentucky before release: RP-HPLC for purity, LC-MS for identity, Karl Fischer titration for water, LAL for endotoxin and USP <71> for sterility. The results for the lot now shipping are in the certificate panel on this page, and the certificate number, key and QR code can be checked on the verify page. These are in-house results from PrymaLab Analytical, not an independent test, and the lab is not accredited to ISO 17025. The third-party testing guarantee on this page still applies: if any independent laboratory finds the wrong compound, or less than the stated purity or amount, the order is refunded and the cost of the test is reimbursed.
Frequently asked questions
What does DES(1-3) mean?
Des means without: the protein lacks residues 1 to 3 of IGF-1, the tripeptide Gly-Pro-Glu. Everything from threonine 4 to the C-terminal alanine is the human IGF-1 sequence, 67 residues in all, folded with three intrachain disulfides.
How does IGF-1 DES differ from IGF-1 LR3?
LR3 lengthens IGF-1 with a 13-residue extension and swaps residue 3; DES shortens it by removing the first three residues. Both weaken binding to IGF-binding proteins. DES also occurs naturally, in bovine colostrum and human brain, while LR3 is an engineered fusion protein.
Why was the truncated form more potent in cell assays?
Not because it binds the IGF-1 receptor better. In L6 myoblast studies its receptor binding was about the same as IGF-1, but binding proteins secreted by the cells held IGF-1 far more tightly, leaving more of the truncated form free to act on the cells.
How should the vial be stored?
Sealed at −20 °C, dry and dark, without repeated freeze-thaw cycles, as the certificate states. Allow the vial to reach room temperature before opening it. A reconstituted solution should go to 2 to 8 °C, protected from light, for a period your laboratory has set.
Where can I see the certificate?
The certificate panel on this page covers the lot now shipping, with purity, LC-MS identity, water, endotoxin and sterility. Compare its lot number with the vial label, and use the verify page to confirm a certificate by number and key.
Is IGF-1 DES for human use?
No. It is sold for laboratory research only and has no approval for human or veterinary use from the FDA or any other authority. It must not be given to people or animals.
References
- Francis GL, Upton FM, Ballard FJ, et al. Insulin-like growth factors 1 and 2 in bovine colostrum. Sequences and biological activities compared with those of a potent truncated form. Biochem J. 1988;251(1):95-103. DOI · PubMed
- Sara VR, Carlsson-Skwirut C, Bergman T, et al. Identification of Gly-Pro-Glu (GPE), the aminoterminal tripeptide of insulin-like growth factor 1 which is truncated in brain, as a novel neuroactive peptide. Biochem Biophys Res Commun. 1989;165(2):766-71. DOI · PubMed
- Ballard FJ, Francis GL, Ross M, et al. Natural and synthetic forms of insulin-like growth factor-1 (IGF-1) and the potent derivative, destripeptide IGF-1: biological activities and receptor binding. Biochem Biophys Res Commun. 1987;149(2):398-404. DOI · PubMed
- Bagley CJ, May BL, Szabo L, et al. A key functional role for the insulin-like growth factor 1 N-terminal pentapeptide. Biochem J. 1989;259(3):665-71. DOI · PubMed
- Ballard FJ, Knowles SE, Walton PE, et al. Plasma clearance and tissue distribution of labelled insulin-like growth factor-I (IGF-I), IGF-II and des(1-3)IGF-I in rats. J Endocrinol. 1991;128(2):197-204. DOI · PubMed
- Tomas FM, Knowles SE, Owens PC, et al. Increased weight gain, nitrogen retention and muscle protein synthesis following treatment of diabetic rats with insulin-like growth factor (IGF)-I and des(1-3)IGF-I. Biochem J. 1991;276 ( Pt 2)(Pt 2):547-54. DOI · PubMed
Research use only
For laboratory research use only. IGF-DES 2mg is not a drug, food, cosmetic or dietary supplement, is not approved by the FDA or any comparable authority for human or veterinary use, and must not be given to people or animals. It is sold to qualified researchers and institutions, and the buyer is responsible for lawful handling and disposal.
Other formats of IGF-DES
IGF-DES is also stocked as IGF-1 LR3 Nasal Spray, IGF1 LR3 1mg/ml preloaded 3ml pen and IGF1 LR3 1MG. Each listing states its own quantity and concentration, and the pen and vial comparison explains what changes between formats.
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