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Longevity & Bioregulators

Cortagen Australia — Ala-Glu-Asp-Pro Tetrapeptide

Cortagen research peptide vial — TXLABS, ≥98% HPLC

From $99 AUD · ≥98% HPLC purity · third-party COA · ships Australia-wide

What is Cortagen?

Cortagen (Ala-Glu-Asp-Pro, AEDP) is a synthetic tetrapeptide bioregulator associated with the brain and cerebral cortex. Part of the Khavinson short-peptide class, it is studied in preclinical research on neuronal tissue and gene-expression regulation. Cortagen is supplied as a research reference material for investigations into cortical peptide signalling.

Specifications

What the research covers

Cortagen is a synthetic tetrapeptide, Ala-Glu-Asp-Pro, produced within the ultrashort peptide bioregulator programme of Professor Vladimir Khavinson and colleagues at the St Petersburg Institute of Bioregulation and Gerontology. It is the member named for the cerebral cortex, and the neurological characterisation associated with it originates in that programme.

Two naming problems attach to this compound and both are worth settling before anything else. The first is transliteration. Russian-language sources render the name in Latin script inconsistently, and the compound appears as both Cortagen and Korthagen, including in tabulations produced by the originating group itself. Trade names from this programme are not chemical identifiers: there is no international nonproprietary name, no consistent CAS practice across suppliers, and nothing preventing two vendors selling different material under one label. The sequence is the identifier. The second is a different confusion entirely: Cortexin is a polypeptide fraction extracted from animal brain tissue, an undefined mixture with no single sequence, no single molecular weight and no meaningful purity figure. Cortagen is a defined synthetic tetrapeptide. They are routinely discussed together and they are not the same kind of material.

On mechanism, the originating literature proposes direct interaction with DNA or chromatin-associated proteins producing tissue-selective changes in gene expression rather than classical receptor binding. That is a hypothesis internal to one research tradition, argued chiefly from modelling and from that tradition's own experiments, and it has not been established independently.

The evidence caveat is unavoidable here as elsewhere in the family: a small number of originating laboratories, largely Russian-language publication over several decades, reporting conventions unlike the international literature, and very limited independent replication.

TXLABS supplies cortagen as an analytical reference material for laboratory research only. It is not an approved therapeutic good in Australia and is not supplied for human or veterinary administration.

Reading the certificate

Proline complicates chromatography in a way that is worth anticipating on a certificate. The bond preceding a proline residue interconverts slowly between cis and trans conformations, and when that interconversion is slow relative to the chromatographic timescale it produces broadened or genuinely split peaks that are conformational, not compositional. A chromatogram showing a shoulder on the main peak may therefore be reporting one molecule in two conformations rather than an impurity, and equally a real related substance can hide beneath the broadening. Variable-temperature runs, which sharpen the peak as interconversion speeds up, and mass spectrometry taken across the peak both distinguish the two cases. Ask which was done. TXLABS publishes third-party certificates for tested lots in the CoA library; none is currently published for cortagen, and the certificate for the lot supplied is available on request to support@txlabs.bio.

Storage and handling

Cortagen is a short, polar, acidic tetrapeptide, so the routine storage principles apply: -20 °C for the lyophilised cake, desiccated and dark, with 2-8 °C acceptable for a vial in current use, and 2-8 °C in the dark once reconstituted with single-use aliquots in preference to repeated freeze-thaw. It is hygroscopic on account of the two acidic side chains and should be equilibrated to room temperature sealed before the closure is broken. The proline gives it one distinctive property worth knowing about in solution: proline-containing peptides interconvert slowly between cis and trans forms of the preceding amide bond, and that equilibrium is temperature-dependent. A solution that has just been warmed from refrigeration has not necessarily reached its equilibrium distribution, which matters for anyone running comparative chromatography. In Australian conditions the usual advice holds and is worth repeating for a compound often bought in summer: parcels left in vehicles or unshaded letterboxes routinely exceed 40 °C, so collect promptly and refrigerate on receipt.

Working out concentration

Cortagen is supplied in a 20 mg vial. Reconstituted with 2 mL of bacteriostatic water it gives 10 mg/mL; with 4 mL, 5 mg/mL; with 5 mL, 4 mg/mL; with 8 mL, 2.5 mg/mL. The arithmetic is the same division for every vial in the catalogue, but the vial masses in this family vary between 10 and 20 mg from compound to compound, so a volume copied from a neighbouring product will give the wrong figure. Record the vial mass alongside the volume rather than the concentration alone. The reconstitution calculator performs the conversion for any combination. Concentration examples only, not a protocol.

How it relates to adjacent compounds

Cortagen is cartalax with a proline appended, and crystagen is cortagen with its N-terminal alanine removed, so the three form a short chain of single-residue relationships that also makes each a plausible synthesis-related impurity of the others. Prostamax is the other proline-containing member of the family and shares the same conformational chromatography behaviour. Further out, thymalin is the catalogue's example of the tissue-extract category that Cortexin belongs to, and reading it clarifies why an undefined fraction and a defined tetrapeptide cannot be assessed on the same terms. These are structural and categorical relationships and say nothing about comparative activity.

Frequently asked questions

Is Korthagen the same thing as Cortagen? +
They are two Latin-script renderings of the same Russian name, and the same sequence, Ala-Glu-Asp-Pro, sits behind both. The inconsistency comes from transliteration rather than from chemistry. It matters because trade names in this family are not regulated identifiers, so a spelling variation in a catalogue or a certificate is not by itself evidence of a different molecule, nor is a matching spelling evidence of the same one.
How does cortagen differ from Cortexin? +
Fundamentally. Cortagen is a synthetic tetrapeptide with one sequence and one molecular weight. Cortexin is a polypeptide fraction extracted from animal brain tissue: a mixture of peptides of varying lengths with no single sequence, no single mass and no meaningful purity percentage, for which source species, herd origin and viral and TSE safety documentation are material questions. They are discussed together in the same literature but they are different categories of material.
Why can a proline-containing peptide show split chromatographic peaks? +
The amide bond preceding a proline residue interconverts between cis and trans forms slowly, on a timescale that can be comparable to a chromatographic separation. When it is slow enough, the two conformers travel through the column as distinct populations and appear as a broadened or split peak. It looks like an impurity but it is one molecule in two shapes, and warming the column usually merges the peaks.
How would you tell a conformer from a genuine impurity? +
Two straightforward tests. Run the separation at elevated column temperature: conformational splitting collapses into a single sharper peak as interconversion accelerates, while a real impurity stays separate. And take mass spectra across the peak: two conformers of one molecule give identical masses throughout, whereas a related substance gives a different mass under the shoulder.
Is the proposed gene-expression mechanism established for cortagen? +
No. The proposal that ultrashort peptides enter cells and interact directly with DNA or chromatin-associated proteins to modulate gene expression comes from the originating research tradition and rests largely on molecular modelling together with that tradition's own experimental work. It has not been confirmed by independent structural or pharmacological studies, and it should be read as a working hypothesis rather than a described mechanism.
What is cortagen's status under Australian law? +
It is not registered on the ARTG, and scheduling is set by the Poisons Standard, which the TGA revises on a regular cycle, so any statement about schedule is date-dependent and must be checked against the current instrument. The TGA has published guidance on responsibilities when importing, compounding and supplying unapproved peptide products, and has stated that research use only labelling does not legitimise an unlawful supply. See tga.gov.au.

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