A practical reference on tetrapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-08-22 and is reviewed periodically as new material appears.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Electrospray or MALDI mass spectrometry | Observed mass compared with theoretical 390.35 Da |
| Purity specification | 95 percent or greater by RP-HPLC | Common convention for research-grade peptide |
| Counter-ion | Acetate or trifluoroacetate | Affects net peptide content of a weighed sample |
| Solution storage | −80 °C as single-use aliquots | Repeated freeze–thaw cycles accelerate loss |
| Main degradation route | Aspartimide formation at Asp-Gly | Produces isoaspartate and related species |
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The contaminated vegetable proteins were imported from China in 2006 and early 2007 and used as pet food ingredients. The process of identifying and accounting for the source of the contamination and for how the contaminant causes sickness was ongoing. The first recalls were announced by Menu Foods late on Friday, 16 March 2007 for cat and dog food products in the United States. By 30 March the United States began to ban imports of wheat gluten from China. The Chinese government responded on 4 April by categorically denying any connection to the North American food poisonings refusing to allow inspection of facilities suspected of producing contaminated products. However, on 6 April 2007, the Chinese government told the Associated Press they would investigate the source of the wheat gluten and by 23 April China gave permission to FDA investigators to enter the country. On 25 April Chinese authorities began to shut down and destroy the implicated factories and detain their managers. The following day, China's Foreign Ministry said it had banned the use of melamine in food products, admitting that products containing melamine had cleared customs while continuing to dispute the role of melamine in causing pet deaths. China also vowed to cooperate with U.S. investigators to find the "real cause" of pet deaths. The United States Senate held an oversight hearing on the matter by 12 April. The economic impact on the pet food market has been extensive, with Menu Foods losing roughly US$30 million alone from the recall.
Specific terms are used to describe nerves and their actions. A nerve that supplies information to the brain from an area of the body, or controls an action of the body is said to innervate that section of the body or organ. Other terms relate to whether the nerve affects the same side ("ipsilateral") or opposite side ("contralateral") of the body, to the part of the brain that supplies it.
== Side effects == Prucalopride has been given orally to ~2700 patients with chronic constipation in controlled clinical trials. The most frequently reported side effects are headache and gastrointestinal symptoms (abdominal pain, nausea or diarrhea) and suicidal ideation. Such reactions occur predominantly at the start of therapy and usually disappear within a few days with continued treatment.
Sources: en.wikipedia.org
Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer that accounts for ten to fifteen percent of all breast cancer cases. Chemotherapy is the only viable current treatment for TNBC because the loss of target receptors inherent to the disease causes cancer cells to resist therapeutic pharmaceuticals. The three-way junction in the φ29 DNA packaging motor can help sensitize TNBC cells to chemotherapy using a siRNA drug delivery mechanism to inhibit TNBC growth and volume. This treatment can also be combined with anti-cancer drugs like Doxorubicin to enhance therapeutic effects. Bacteriophage Bacteriophage pRNA φ29 DNA polymerase
(The times are half-lives.) This proved that the unknown radioactive source originated from the decay of uranium and, coupled with the previous observation that the source was different chemically from all known elements, proved beyond all doubt that a new element had been discovered. McMillan and Abelson published their results in a paper entitled Radioactive Element 93 in the Physical Review on May 27, 1940. They did not propose a name for the element in the paper, but they soon decided on the name neptunium since Neptune is the next planet beyond Uranus in the Solar System, which uranium is named after. McMillan and Abelson's success compared to Nishina and Kimura's near miss can be attributed to the favorable half-life of 239Np for radiochemical analysis and quick decay of 239U, in contrast to the slower decay of 237U and extremely long half-life of 237Np.
Pioglitazone (Actos), France and Germany have suspended its sale after a study suggested the drug could raise the risk of bladder cancer. Rosiglitazone (Avandia), which was put under selling restrictions in the US and withdrawn from the market in Europe due to some studies suggesting an increased risk of cardiovascular events. Upon re-evaluation of new data in 2013, the FDA lifted the restrictions. Lobeglitazone (Duvie), approved for use in South Korea Experimental, failed and non-marketed agents include:
Overview article — Chamary J, Hurst LD (June 2009). "How Trivial DNA Changes Can Hurt Health". Scientific American. 300 (6): 46–53. doi:10.1038/scientificamerican0609-46. PMID 19485088. "WatCut: An on-line tool for restriction analysis, silent mutation scanning, and SNP-RFLP analysis". University of Waterloo. April 17, 2014. Archived from the original on May 4, 2020. Retrieved November 22, 2014.
Sources: en.wikipedia.org
Mass spectrometry provides the identity check, because the observed mass is compared with the theoretical mass of the AEDG sequence. Chromatography separates and quantifies impurities but does not by itself prove which peptide is present. The two techniques are normally used together.
Yes. Trifluoroacetate and acetate ions remain associated with the peptide after purification, so a weighed quantity of powder contains less peptide than the nominal mass suggests. Certificates that report net peptide content rather than raw weight are more directly comparable between suppliers.
Dilute aqueous solutions are less stable than the dry powder and are usually aliquoted and frozen to avoid repeated freeze–thaw cycles. Lyophilised material is best stored desiccated at −20 °C, protected from light. Working solutions are typically prepared fresh from a frozen aliquot.
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.