Everything below concerns Tetrapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-29. Numbers and descriptions here follow the published literature rather than marketing material.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four residues, linear chain |
| Residue sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Calculated mass | 390.3 daltons | Value for the free, uncharged form |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility | Freely soluble in water | Often handled as a salt form |
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
== Gene expression assays == Reporter genes can be used to assay for the expression of a gene of interest that is normally difficult to quantitatively assay. Reporter genes can produce a protein that has little obvious or immediate effect on the cell culture or organism. They are ideally not present in the native genome to be able to isolate reporter gene expression as a result of the gene of interest's expression. To activate reporter genes, they can be expressed constitutively, where they are directly attached to the gene of interest to create a gene fusion. This method is an example of using cis-acting elements where the two genes are under the same promoter elements and are transcribed into a single messenger RNA molecule. The mRNA is then translated into protein. It is important that both proteins be able to properly fold into their active conformations and interact with their substrates despite being fused. In building the DNA construct, a segment of DNA coding for a flexible polypeptide linker region is usually included so that the reporter and the gene product will only minimally interfere with one another. Reporter genes can also be expressed by induction during growth. In these cases, trans-acting elements, such as transcription factors are used to express the reporter gene. Reporter gene assay have been increasingly used in high throughput screening (HTS) to identify small molecule inhibitors and activators of protein targets and pathways for drug discovery and chemical biology. Because the reporter enzymes themselves (e.g.
With mutual arrangement with Leuven, he became professor in both universities from 1962, dividing his time between Leuven and New York. In 1974, the same year he received his Nobel Prize, he founded the ICP, which would later be renamed the de Duve Institute. He became emeritus professor of the University of Louvain in 1985, and of Rockefeller in 1988. De Duve was granted the rank of Viscount in 1989 by King Baudouin of Belgium. He was also a recipient of Francqui Prize, Gairdner Foundation International Award, Heineken Prize, and E.B. Wilson Medal. In 1974, he founded the International Institute of Cellular and Molecular Pathology in Brussels, eventually renamed the de Duve Institute in 2005. He was the founding President of the L'Oréal-UNESCO For Women in Science Awards. He died by legal euthanasia after long suffering from cancer and atrial fibrillation.
The presidents of the council were clearly the heads of government of the kingdom, holding the executive power that absolute monarchs had, but were restricted by the controlling power of the National Congress. With the advent of the Republic in the 5 October 1910 revolution, the head of government was renamed President of the Ministry (Presidente do Ministério). During this period the heads of government were under the strong power of the parliament and often fell due to parliamentary turmoils and social instability. With the 28 May 1926 coup d'état, and eventually, after the formation of the Estado Novo quasi-fascist dictatorial regime of António de Oliveira Salazar, the prime minister was again named President of the Council of Ministers, and was nominally the most important figure in the country. First Salazar and then Marcello Caetano occupied this post for almost 42 years. With the Carnation Revolution came the prime minister, which replaced the president of the council.
=== Construction === Coral reefs in places such as the East African coast are used as a source of building material. Ancient (fossil) coral limestone, notably including the Coral Rag Formation of the hills around Oxford (England), was once used as a building stone, and can be seen in some of the oldest buildings in that city including the Saxon tower of St Michael at the Northgate, St. George's Tower of Oxford Castle, and the medieval walls of the city.
Once across the interface, the tails and loops form whatever bonds are favorable. In the case of polymer-on-polymer surfaces, this means more van der Waals forces. While these may be brittle, they are quite strong when a large network of these bonds is formed. The outermost layer of each surface plays a crucial role in the adhesive properties of such interfaces, as even a tiny amount of interdigitation – as little as one or two tails of 1.25 angstrom length – can increase the van der Waals bonds by an order of magnitude.
Sources: en.wikipedia.org
A raw tomato is 95% water, 4% carbohydrates, and less than 1% each of fat and protein (table). In a reference amount of 100 grams (3.5 oz), raw tomatoes supply 18 calories and 16% of the Daily Value of vitamin C, but otherwise have low micronutrient content (table).
Occurs at rest or minimal exertion and usually lasts more than 20 minutes (if nitroglycerin is not administered) Being severe (at least Canadian Cardiovascular Society Classification 3) and of new onset (i.e. within 1 month) Occurs with a crescendo pattern (brought on by less activity, more severe, more prolonged or increased frequency than previously). Fifty percent of people with unstable angina will have evidence of necrosis of the heart's muscular cells based on elevated cardiac serum markers such as creatine kinase isoenzyme (CK)-MB and troponin T or troponin I, and thus have a diagnosis of non-ST elevation myocardial infarction.
Nervous tissue is composed of neurons, also called nerve cells, and neuroglial cells. Four types of neuroglia found in the CNS are astrocytes, microglial cells, ependymal cells, and oligodendrocytes. Two types of neuroglia found in the PNS are satellite glial cells and Schwann cells. In the central nervous system (CNS), the tissue types found are grey matter and white matter. The tissue is categorized by its neuronal and neuroglial components.
== Phytocannabinoids == The classical cannabinoids are concentrated in a viscous resin produced in structures known as glandular trichomes. At least 113 different cannabinoids have been isolated from the Cannabis plant. All classes derive from cannabigerol-type (CBG) compounds and differ mainly in the way this precursor is cyclized. The classical cannabinoids are derived from their respective 2-carboxylic acids (2-COOH) by decarboxylation (catalyzed by heat, light, or alkaline conditions).
Sources: en.wikipedia.org
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.
Epithalamin refers to a crude preparation derived from bovine pineal tissue, which contains many components. Epitalon is a single synthetic tetrapeptide identified from that material and produced by chemical synthesis. The two names are sometimes confused because early reports treated the synthetic peptide as an active fragment of the extract.
It has been registered for clinical use in Russia, where it is associated with a small family of short peptides. In most other jurisdictions it is not an approved medicine and is traded as a research chemical. Regulatory status varies by country and changes over time.
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.