The short version of tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-21. Anything still debated is marked as such rather than presented as settled.
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 proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
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.
The most frequently cited laboratory finding is that AEDG increased telomerase activity and extended telomere length in cultured human somatic cells. That work used fetal fibroblast strains and reported changes in enzyme activity alongside altered division counts. Replication by unrelated groups has been limited, and the published record is largely a single-laboratory series rather than a multi-centre programme. The result supports a hypothesis about peptide influence on gene expression in cell culture; it does not by itself establish an effect on telomere length in living animals or in people.
Animal and clinical reports appear mainly in Russian-language journals from the 1990s and 2000s, covering endpoints such as melatonin rhythm, lifespan in aged rodents, and retinal function. Many of these papers involve small groups, lack blinding or placebo comparison, and are difficult to retrieve through indexed databases. Review articles published in English generally summarise the claims without reanalysing the underlying data. Because no large randomised trial exists, the clinical importance of these reported effects stays unresolved and is properly described as an open question.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Tetrapeptide, often abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free peptide, unmodified termini |
| Molecular weight | ~390.35 Da | Calculated for the free acid form |
| Appearance | White to off-white powder | Typical lyophilized product form |
| Solubility class | Freely soluble in water | Two acidic residues dominate ionic character |
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
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.
（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.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. The chromatogram shows the main peak and any truncated or oxidised by-products, while the mass spectrum confirms the expected 390 dalton mass. Amino acid analysis can corroborate composition when a sample's origin is uncertain. Counterion content, particularly residual trifluoroacetate from purification, is frequently reported alongside purity because it shifts the net mass of the solid.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
=== Marketed === Daridorexant (nemorexant; Quviviq) – dual OX1 and OX2 antagonist – approved for insomnia in January 2022, formerly under development for sleep apnea – half-life 8 hours Fazamorexant (Mengping) – dual OX1 and OX2 antagonist – approved for insomnia in China in May 2026 – half-life 2–4 hours Lemborexant (Dayvigo) – dual OX1 and OX2 antagonist – approved for insomnia in December 2019 and released June 1 2020, under development for circadian rhythm sleep disorders, chronic obstructive pulmonary disease, and sleep apnea – half-life 17–55 hours Suvorexant (Belsomra) – dual OX1 and OX2 antagonist – approved for insomnia in August 2014, under development for delirium – half-life 12 hours Vornorexant (Vorzzz) – dual OX1 and OX2 antagonist – approved for insomnia in Japan in August 2025 – half-life 1.5–3 hours
Urocortin 2 (Ucn2) is an endogenous peptide in the corticotrophin-releasing factor (CRF) family. Urocortin II is a 38-amino acid peptide that is a member of the CRF family of peptides. Unlike Urocortin I, Urocortin II is highly selective for the CRF2 receptor and does not show affinity for the CRF binding protein.
NOS Journaal – one of the most important news programmes in the Netherlands, broadcast on all public stations whenever possible. The flagship edition is the 8 pm bulletin on NPO 1, often called achtuurjournaal, supplemented by two shorter editions at 6pm & midnight and hourly bulletins throughout the day. NOS Jeugdjournaal – A news programme aimed at 8–12-year-olds, aired on children's channel NPO Zapp. It is broadcast at 7pm and lasts 20 minutes, and a short bulletin is broadcast every weekday at 8:45 am when primary school starts. NOS Studio Sport – A sports programme covering the most popular sports. It has the right to broadcast major sports tournaments, like the Olympic Games and the FIFA World Cup and UEFA Euro. The NOS no longer has the right to broadcast full matches of the Eredivisie, but Studio Sport Eredivisie still provides summaries of matches played. The programme also covers matches and competitions in other sports, most notably tennis, ice skating, cycling, and field hockey. The editorial staff is also responsible for the NOS Sportjournaal, a news programme about sport, and NOS Studio Voetbal, a football talkshow on Sunday evening about the Eredivisie, the Netherlands national team and other news in football. NOS Journaal op 3 – a 60-second news bulletin aimed at teenagers and young adults, aired on NPO 3, since 2011 called NOS op 3. NOS Den Haag Vandaag – a daily roundup of events from parliamentary sessions and political reports, produced in cooperation with the NOS, NTR and BNNVARA.
Sources: en.wikipedia.org
=== History === Fu, Jia-Chen; King, Michelle; Klein, Jakob, eds. (2025). Modern Chinese Foodways. MIT Press. ISBN 9780262381642. Chang, Kwang-chih (1977). Food in Chinese Culture: Anthropological and Historical Perspectives. New Haven: Yale University Press. ISBN 0300019386. David R. Knechtges, "A Literary Feast: Food in Early Chinese Literature," Journal of the American Oriental Society 106.1 (1986): 49–63. Newman, Jacqueline M. (2004). Food Culture in China. Westport, Conn.: Greenwood Press. ISBN 0313325812. Roberts, J. A. G. (2002). China to Chinatown: Chinese Food in the West. London: Reaktion. ISBN 1861891334. Sterckx, Roel. Food, Sacrifice, and Sagehood in Early China. New York: Cambridge University Press, 2011 (2015). Sterckx, Roel. Chinese Thought. From Confucius to Cook Ding. London: Penguin, 2019. Swislocki, Mark (2009). Culinary Nostalgia: Regional Food Culture and the Urban Experience in Shanghai. Stanford, CA: Stanford University Press. ISBN 9780804760126. Waley-Cohen, Joanna (2007). "Celebrated Cooks of China's Past". Flavor & Fortune. 14 (4): 5–7, 24. Archived from the original on 2 April 2015. Endymion Wilkinson, "Chinese Culinary History (Feature Review)," China Review International 8.2 (Fall 2001): 285–302. Wilkinson, Endymion (2022). Chinese History: A New Manual. Cambridge, MA: Harvard University Press. ISBN 978-0674260184. Wu, David Y. H.; Cheung, Sidney C. H. (2002). The Globalization of Chinese Food. Richmond, Surrey: Curzon. ISBN 0700714030.
January 23: Law granting women the right to vote in elections for commercial courts. April 1: Law on mutual aid societies: these can notably be founded by women, and if the woman is married, she does not need her husband's involvement to do so. 1900
Forequarter Neck – neck chops Shoulder – shoulder chops, shoulder roast (usually boned and rolled) Rib-eye Breast Knuckle Loin Rib-loin – racks, frenched cutlets, spare ribs Mid-loin – striploin (backstrap), loin chops Tenderloin Flap Full leg – leg roast (may be boned and rolled), leg chops. A short-cut leg is a full leg without the chump; a carvery leg is a short-cut leg without the thick flank Chump (rump) – chump chops, rump steak Thick flank (knuckle) – schnitzel Topside & silverside – steaks Shank
Sources: en.wikipedia.org
Certain atomic nuclei are able to absorb radio frequency (RF) energy when placed in an external magnetic field; the resultant evolving spin polarization can induce an RF signal in a radio frequency coil and thereby be detected. In other words, the nuclear magnetic spin of protons in the hydrogen nuclei resonates with the RF incident waves and emit coherent radiation with compact direction, energy (frequency) and phase. This coherent amplified radiation is then detected by RF antennas close to the subject being examined. It is a process similar to masers. In clinical and research MRI, hydrogen atoms are most often used to generate a macroscopic polarized radiation that is detected by the antennas. Hydrogen atoms are naturally abundant in humans and other biological organisms, particularly in water and fat. For this reason, most MRI scans essentially map the location of water and fat in the body. Pulses of radio waves excite the nuclear spin energy transition, and magnetic field gradients localize the polarization in space. By varying the parameters of the pulse sequence, different contrasts may be generated between tissues based on the relaxation properties of the hydrogen atoms therein. Since its development in the 1970s and 1980s, MRI has proven to be a versatile imaging technique. While MRI is most prominently used in diagnostic medicine and biomedical research, it also may be used to form images of non-living objects, such as mummies.
=== United Kingdom === Rhodesia was originally a self-governing British crown colony. Although decolonisation in Africa had begun after World War II, it began accelerating in the early 1960s, causing Britain to negotiate independence rapidly with several of its colonies. During this period, it adopted a foreign policy called NIBMAR, or No Independence Before Majority African Rule, mandating democratic reforms that placed governance in the hands of the majority black Africans. The governing white minority of Rhodesia, led by Ian Smith, opposed the policy and its implications. On 11 November 1965, Rhodesia's minority white government made a unilateral declaration of independence (UDI) from the United Kingdom, as it became apparent that negotiations would not lead to independence under the white regime. The United Kingdom government immediately brought in legislation (Southern Rhodesia Act 1965) which formally abolished all Rhodesian government institutions. This move made life difficult for Rhodesian citizens who wished to travel internationally as passports issued by Rhodesia's UDI administration were not recognised as valid; in January 1966, the British issued a statement accepting as valid any passport issued before the declaration of independence and allowing six-month United Kingdom passports to be granted when they expired – provided that the bearer declared they did not intend to aid the UDI Rhodesian government.
==== MeSH D12.776.624.664.700 – proto-oncogene proteins ==== MeSH D12.776.624.664.700.100 – cyclin d1 MeSH D12.776.624.664.700.110 – fibroblast growth factor 4 MeSH D12.776.624.664.700.112 – fibroblast growth factor 6 MeSH D12.776.624.664.700.114 – fms-like tyrosine kinase 3 MeSH D12.776.624.664.700.120 – receptor, fibroblast growth factor, type 3 MeSH D12.776.624.664.700.130 – muts homolog 2 protein MeSH D12.776.624.664.700.148 – myeloid-lymphoid leukemia protein MeSH D12.776.624.664.700.167 – proto-oncogene proteins c-abl MeSH D12.776.624.664.700.168 – proto-oncogene proteins c-akt MeSH D12.776.624.664.700.169 – proto-oncogene proteins c-bcl-2 MeSH D12.776.624.664.700.170 – proto-oncogene proteins c-bcl-6 MeSH D12.776.624.664.700.171 – proto-oncogene proteins c-bcr MeSH D12.776.624.664.700.172 – proto-oncogene proteins c-cbl MeSH D12.776.624.664.700.174 – proto-oncogene proteins c-crk MeSH D12.776.624.664.700.175 – proto-oncogene proteins c-ets MeSH D12.776.624.664.700.175.100 – proto-oncogene protein c-ets-1 MeSH D12.776.624.664.700.175.200 – proto-oncogene protein c-ets-2 MeSH D12.776.624.664.700.175.400 – proto-oncogene protein c-fli-1 MeSH D12.776.624.664.700.175.600 – ternary complex factors MeSH D12.776.624.664.700.175.600.100 – ets-domain protein elk-1 MeSH D12.776.624.664.700.175.600.300 – ets-domain protein elk-4 MeSH D12.776.624.664.700.177 – proto-oncogene proteins c-fes MeSH D12.776.624.664.700.179 – proto-oncogene proteins c-fos MeSH D12.776.624.664.700.180 – proto-oncogene proteins c-fyn MeSH D12.776.624.664.700.181 – proto-oncogene proteins c-hck MeSH D12.776.624.664.700.182 – proto-oncogene proteins c-jun MeSH D12.776.624.664.700.183 – proto-oncogene proteins c-kit MeSH D12.776.624.664.700.184 – proto-oncogene proteins c-maf MeSH D12.776.624.664.700.185 – proto-oncogene proteins c-mdm2 MeSH D12.776.624.664.700.186 – proto-oncogene proteins c-met MeSH D12.776.624.664.700.187 – proto-oncogene proteins c-mos MeSH D12.776.624.664.700.188 – proto-oncogene proteins c-myb MeSH D12.776.624.664.700.189 – proto-oncogene proteins c-myc MeSH D12.776.624.664.700.191 – proto-oncogene proteins c-pim-1 MeSH D12.776.624.664.700.192 – proto-oncogene proteins c-rel MeSH D12.776.624.664.700.194 – proto-oncogene proteins c-ret MeSH D12.776.624.664.700.195 – proto-oncogene proteins c-sis MeSH D12.776.624.664.700.198 – proto-oncogene proteins c-vav MeSH D12.776.624.664.700.199 – proto-oncogene proteins c-yes MeSH D12.776.624.664.700.200 – proto-oncogene proteins p21(ras) MeSH D12.776.624.664.700.202 – proto-oncogene proteins pp60(c-src) MeSH D12.776.624.664.700.204 – raf kinases MeSH D12.776.624.664.700.204.200 – proto-oncogene proteins b-raf MeSH D12.776.624.664.700.204.500 – proto-oncogene proteins c-raf MeSH D12.776.624.664.700.205 – RNA-binding protein EWS MeSH D12.776.624.664.700.250 – lymphocyte specific protein tyrosine kinase p56(lck) MeSH D12.776.624.664.700.642 – receptor, erbb-2 MeSH D12.776.624.664.700.790 – receptor, erbb-3 MeSH D12.776.624.664.700.800 – receptor, macrophage colony-stimulating factor MeSH D12.776.624.664.700.830 – receptors, thyroid hormone MeSH D12.776.624.664.700.830.500 – thyroid hormone receptors alpha MeSH D12.776.624.664.700.830.750 – thyroid hormone receptors beta MeSH D12.776.624.664.700.915 – RNA-binding protein FUS MeSH D12.776.624.664.700.957 – stathmin MeSH D12.776.624.664.700.967 – wnt1 protein MeSH D12.776.624.664.700.978 – wnt2 protein
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.
No. Epitalon is chemically synthesized, not extracted. It was designed as a short synthetic fragment conceptually related to larger pineal peptides studied in the same research tradition, particularly the extract known as epithalamin. The two are distinct materials with different compositions.
The term bioregulator is used in this research tradition for short peptides proposed to influence gene expression or cell function. Epitalon is grouped with other synthetic short peptides under this label. The term reflects a proposed mechanism rather than an established drug classification.
Small studies with human participants have been reported, chiefly in Russian-language journals, but they are limited in size and design. No large randomised controlled trial with published results is available.