If you have been reading about telomerase and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-09-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
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.
No national medicines regulator has approved epitalon as a therapeutic product. It is generally distributed as a research chemical, and in some jurisdictions selling peptides for human consumption without approval is restricted or prohibited. Certificates of analysis accompanying commercial material vary in which tests are performed, and independent verification of identity and purity is uncommon. Statements about anti-ageing or disease-prevention benefits on vendor pages are marketing claims rather than regulatory findings, a distinction that shapes how the compound is discussed in scientific and popular sources alike.
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.
First, the inward current becomes primarily carried by sodium channels. Second, the delayed rectifier, a potassium channel current, increases to 3.5 times its initial strength. In order for the transition from a calcium-dependent action potential to a sodium-dependent action potential to proceed new channels must be added to the membrane. If Xenopus neurons are grown in an environment with RNA synthesis or protein synthesis inhibitors that transition is prevented. Even the electrical activity of the cell itself may play a role in channel expression. If action potentials in Xenopus myocytes are blocked, the typical increase in sodium and potassium current density is prevented or delayed. This maturation of electrical properties is seen across species. Xenopus sodium and potassium currents increase drastically after a neuron goes through its final phase of mitosis. The sodium current density of rat cortical neurons increases by 600% within the first two postnatal weeks.
The L-type amino acid transporter (LAT1) is a uniporter that mediates the transport of neutral amino acids like L-tryptophan, leucine, histidine, proline, alanine, etc. LAT1 favors the transport of amino acids with large branched or aromatic side chains. The amino acid transporter functions to move essential amino acids into the intestinal epithelium, placenta, and blood-brain barrier for cellular processes such as metabolism and cell signaling. The transporter is of particular significance in the central nervous system as it provides the necessary amino acids for protein synthesis and neurotransmitter production in brain cells. Aromatic amino acids like phenylalanine and tryptophan are precursors for neurotransmitters like dopamine, serotonin, and norepinephrine. LAT1 is a membrane protein of the SLC7 family of transporters and works in conjunction with the SLC3 family member 4F2hc to form a heterodimeric complex known as the 4F2hc complex. The heterodimer consists of a light chain and a heavy chain covalently bonded by a disulfide bond. The light chain is the one that carries out transport, while the heavy chain is needed to stabilize the dimer. There is some controversy over whether LAT1 is an uniporter or an antiporter. The transporter has uniporter characteristics of transporting amino acids into cells in a unidirectional manner down the concentration gradient. However, recently it has been found that the transporter has antiporter characteristics of exchanging neutral amino acids for abundant intracellular amino acids.
HS(CH2)2SH + 2 NR3 + 2 R'I → R'S(CH2)2SR' + 2 [R3NH]I Oxidation of 1,2-ethanedithiol gives a series of oligomers, including the cyclic bis(disulfide). As a 1,2-dithiol, this compound reacts with aldehydes and ketones to give 1,3-dithiolanes, which can be useful intermediates.
Sources: en.wikipedia.org
Milanese resumed football activity only at a regional level, only to officially end it at the end of the 1945-1946 season. In 2021, after 75 years, a new project is initiated: from the union of three clubs from the south of Milan (Accademia Sandonatese and ACD Metanopoli Calcio) Football Club Milanese 1902 is born, whose first team plays in the fifth division of the Italian championship, with a regional youth sector. F.C. Milanese 1902 was recreated with the intention of giving continuity in the football field to its ancestor U.S. Milanese, taking up its history, logo, traditions and club colours. Right now, F.C. Milanese 1902 is playing at the non-professional level with a youth sector of regional level.
== Personal life == Since his playing career ended, Bagwell has spent much of his time with his family while sporadically taking coaching and special assignment positions for the Astros. He is married to Rachel Bagwell, his third wife, with whom he has five children in a blended family. Rachel had three children prior to meeting Jeff. Before his marriage to Rachel, Jeff had two daughters, Blake and Bryce. Bagwell married his first wife, model Shaune Bagwell (née Stauffer), in 1992. He later married Ericka Bagwell, with whom he had his two daughters. Rachel Bagwell was the widow of Greater Houston-area hand surgeon Dr. Michael Brown, the owner and founder of Brown Hand Center. In spite of his professional success, Bagwell has stated that he "doesn't enjoy too much of the spotlight" that follows. While giving a tribute to him during the retirement ceremony of his uniform number, longtime friend and former teammate Brad Ausmus noted several little-known facts. "He liked soccer as much as ... baseball" while growing up in Connecticut. He hit three fewer home runs than his boyhood idol, Carl Yastrzemski, who hit 452. "His baseball card says he's six feet tall. He's closer to 5' 10"." Both Bagwell and Ausmus hit 32 triples in their careers. After his playing career, Bagwell was seen with significantly longer hair. Remarked Ausmus, "I want to confirm he does not have hair extensions." In January 2015, Bagwell reportedly sold his home in the Memorial neighborhood of Houston.
Notably, about half of her graduate and post-graduate trainees in the past decade have identified as female. She has mentored a next generation of academic faculty in nanomedicine and bioengineering at institutions worldwide. Notable alumni from her lab include:
Tianeptine, sold under the brand names Stablon, Tatinol, and Coaxil among others, is an atypical tricyclic antidepressant which is used mainly in the treatment of major depressive disorder, although it may also be used to treat anxiety, asthma, and irritable bowel syndrome. Tianeptine has antidepressant and anxiolytic effects with a relative lack of sedative, anticholinergic, and cardiovascular side effects. It has been found to act as an atypical agonist of the μ-opioid receptor with clinically negligible effects on the δ- and κ-opioid receptors. This may explain part of its antidepressant and anxiolytic effects; however, it is thought that tianeptine also modulates glutamate receptors, and this may also explain tianeptine's antidepressant/anxiolytic effects. Tianeptine was discovered and patented by the French Society of Medical Research in the 1960s. It was introduced for medical use in France in 1983. Currently, tianeptine is approved in France and manufactured and marketed by Laboratories Servier SA; it is also marketed in a number of other European countries under the trade name Coaxil as well as in Asia (including Singapore) and Latin America as Stablon and Tatinol but it is not available in Australia, Canada, New Zealand, Italy or the United Kingdom. In the United States, it is an unregulated drug sold under several names and some of these products have been found to be adulterated with other recreational drugs. It is commonly known by the nickname "gas station heroin".
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.
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.