tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
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.
| Property | Value | Notes |
|---|---|---|
| Storage temperature, dry powder | -20 degrees Celsius or lower | Sealed, dark, low humidity |
| Storage temperature, solution | 2 to 8 degrees Celsius | Short-term use expected |
| Primary purity method | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Identity confirmation | Electrospray mass spectrometry | Compared with calculated mass |
| Typical purity specification | Area percent of 95 or higher | Depends on column and gradient |
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
== Detection == With continuing experience, particularly on the upper continental slope in the Gulf of Mexico, the successful prediction of the presence of tubeworm communities continues to improve; however, chemosynthetic communities cannot be reliably detected directly using geophysical techniques. Hydrocarbon seeps that allow chemosynthetic communities (Guaymas Basin) to exist do modify the geological characteristics in ways that can be remotely detected, but the time scales of co-occurring active seepage and the presence of living communities is always uncertain. These known sediment modifications include (1) precipitation of authigenic carbonate in the form of micronodules, nodules, or rock masses; (2) formation of gas hydrates; (3) modification of sediment composition through concentration of hard chemosynthetic organism remains (such as shell fragments and layers); (4) formation of interstitial gas bubbles or hydrocarbons; and (5) formation of depressions or pockmarks by gas expulsion. These features give rise to acoustic effects such as wipeout zones (no echoes), hard bottoms (strongly reflective echoes), bright spots (reflection enhanced layers), or reverberant layers (Behrens, 1988; Roberts and Neurauter, 1990). Potential locations for most types of communities can be determined by careful interpretation of these various geophysical modifications, but to date, the process remains imperfect and confirmation of living communities requires direct visual techniques.
==== Unintended use ==== It is not safe to calculate divided doses by cutting and weighing medical skin patches, because there's no guarantee that the substance is evenly distributed on the patch surface. For example, fentanyl transdermal patches are designed to slowly release the substance over 3 days. It is well known that cut fentanyl transdermal consumed orally have cause overdoses and deaths. Single blotting papers for illicit drugs injected from solvents in syringes may also cause uneven distribution across the surface.
==== Dll4 ==== Delta-like ligand 4 (Dll4) is a protein with a negative regulatory effect on angiogenesis. Dll4 is a transmembrane ligand, for the notch family of receptors. There have been many studies conducted that have served to determine consequences of the Delta-like Ligand 4. One study in particular evaluated the effects of Dll4 on tumor vascularity and growth. In order for a tumor to grow and develop, it must have the proper vasculature. The VEGF pathway is vital to the development of vasculature that in turn, helps the tumors to grow. The combined blockade of VEGF and Dll4 results in the inhibition of tumor progression and angiogenesis throughout the tumor. This is due to the hindrance of signaling in endothelial cell signaling which cuts off the proliferation and sprouting of these endothelial cells. With this inhibition, the cells do not uncontrollably grow, therefore, the cancer is stopped at this point. if the blockade, however, were to be lifted, the cells would begin their proliferation once again.
Sources: en.wikipedia.org
==== Serious illness ==== Serious illness may result in low blood sugar. Severe disease of many organ systems can cause hypoglycemia as a secondary problem. Hypoglycemia is especially common in those in the intensive care unit or those in whom food and drink is withheld as a part of their treatment plan. Sepsis, a common cause of hypoglycemia in serious illness, can lead to hypoglycemia through many ways. In a state of sepsis, the body uses large amounts of glucose for energy. Glucose use is further increased by cytokine production. Cytokines are a protein produced by the body in a state of stress, particularly when fighting an infection. Cytokines may inhibit glucose production, further decreasing the body's energy stores. Finally, the liver and kidneys are sites of glucose production, and in a state of sepsis those organs may not receive enough oxygen, leading to decreased glucose production due to organ damage. Other causes of serious illness that may cause hypoglycemia include liver failure and kidney failure. The liver is the main site of glucose production in the body, and any liver failure or damage will lead to decreased glucose production. While the kidneys are also sites of glucose production, their failure of glucose production is not significant enough to cause hypoglycemia. Instead, the kidneys are responsible for removing insulin from the body, and when this function is impaired in kidney failure, the insulin stays in circulation longer, leading to hypoglycemia.
Cooking in water causes the loss of some of the water-soluble elements, in particular vitamin C, especially when the tubers are peeled. Thus, in the case of a cooking of 25 to 30 minutes in boiling water, peeled potatoes can lose up to 40% of their vitamin C, 10% if they are cooked with the skin (in this last case, there remains 13 mg of vitamin C for 100 g of vegetable). These losses are added to those induced by the storage time, about 50% after three months. Other preparation methods are even more aggressive for vitamin C, but also for B vitamins; for example, pureeing causes up to 80% loss in vitamin C, and frying 60%. Nevertheless, a 100 g serving of processed potato products can provide 10–50% of the recommended daily allowance of vitamin C for an adult. Cooking with fat, especially frying, can lead to the formation of acrylamide, a substance that is probably carcinogenic to humans, especially if cooked for too long at high temperatures. This reaction occurs when potatoes contain too many reducing sugars (glucose and fructose); their rate, which should not exceed 0.4 to 0.6% of the fresh weight, depends on the variety, the maturity of the tubers and the storage conditions, low temperatures, below 8 °C, favoring the retrogradation of the starch into reducing sugars. The potatoes known as "for consumption", i.e. which were harvested with complete maturity, can be preserved several weeks, provided that they are stored in a room that is ventilated, fresh (between 8 and 9 °C) but sheltered from the frost, and obscure because the light makes them green.
==== Antibiotics ==== In addition to established uses such as insulin administration, the subcutaneous route has increasingly been investigated for the delivery of selected antibiotics as an alternative to intravenous therapy in specific clinical contexts. Available pharmacokinetic and clinical evidence indicates that several time-dependent agents, including β-lactams (e.g. ceftriaxone) and glycopeptides (e.g. teicoplanin), can achieve systemic exposures comparable to intravenous administration while avoiding the need for venous access. This strategy may be particularly relevant for patients with difficult venous access, within outpatient parenteral antimicrobial therapy programs, and in palliative care settings; however, its use remains largely off-label and is supported primarily by observational studies and pharmacokinetic data.
=== H2 Relaxin === In the human ovary, H2 relaxin is produced by the corpus luteum and by Granulosa cells from large antral follicles. Research has shown that the relaxin gene is expressed once the Granulosa cells have reached a certain luteinised status, by which Granulosa cells differentiate into Luteal cells. Therefore, it can act as a good biomarker in relation to Granulosa cell differentiation status. Relaxin is produced to support early pregnancy until the placenta can take over. Relaxin plays a key role in implantation and placenta formation. The relaxin receptor RXFP1 is found on myometrial cells. In rats, it has been linked playing a role in the spacing between embryos in the uterus. RXFP1 is also located on endometrial stromal cells where it can induce cyclic adenosine monophosphate (cAMP). cAMP is a molecule which is necessary for the functional changes in the endometrium to form the decidual lining, where the blastocyst can implant. This results in neo-angiogenesis and endometrial thickening, both linked to early pregnancy development.
Sources: en.wikipedia.org
=== Alcohols === Alcohols generally have weak molecular ion peaks due to the strong electronegativity of oxygen. “Alpha” cleavage is common due to the resonance stabilization. The largest alkyl group will be lost.
== Benefits to fresh produce == Modifying the atmosphere inside fresh produce packaging to provide lowered levels of O2 and elevated levels of CO2 is beneficial for many fresh produce items and "can reduce respiration, decrease ethylene production and action, retard tissue ripening and softening, retard chlorophyll degradation and biosynthesis of carotenoids and anthocyanins, reduce enzymatic browning, alleviate physiological disorders and chilling injury, retard development of decay, and maintain nutritional quality of produce. The effect of decreased O2 and increased CO2 on senescence and ripening process are additive and can be synergistic." "In vegetative tissues MAP can also reduce leaf regrowth (green onion and leek), stem toughening (asparagus), and leaf sprouting and rooting in root vegetables (parsnip, radishes). The delay of ripening and senescence of fruits and vegetables also reduces their susceptibility to pathogens."
=== May === May 5, 2011: Portugal Portugal's Minister of Finance Teixeira dos Santos warns that the upcoming bail-out package of €78 billion is expected to shift Portugal into recession for at least 2 years.
== External links == RM-ODP Resource site Open Distributed Processing - Reference Model RM-ODP information at LAMS, Swiss Federal Institute of Technology, Lausanne (EPFL), Switzerland. Official Record of the ANSA project Computing Laboratory, University of Kent, Canterbury UK. FORMOSA (Formalisation of ODP Systems Architecture), University of Stirling, UK. Distributed and Cooperative Systems, UMPC, Paris, France. ILR, Networks and ComputerScience Department of ENST, Paris France. Distributed Systems Technology Center, Australia. Open Distributed Processing: Unplugged! a simple introduction by Ian Joyner.
=== Mass separation === The traditional IM-MS instrument uses a time‐of‐flight (TOF) mass spectrometer interfaced to an IMS. The TOF-MS has many advantages including the high speed of data acquisition and good sensitivity. Since mass spectral data is acquired on a microsecond time scale, multiple mass spectra are collected for each IMS spectrum (acquired on millisecond timescale). The quadrupole mass spectrometer has also been coupled to an IMS, although at a slower scan rate. Other mass spectrometers including the ion trap, Fourier transform ion cyclotron resonance (FT-ICR), or magnetic sector mass spectrometers have also been coupled with different IMS for various applications. Additionally, hybrid mass spectrometers have been interfaced to more than one ion mobility cell for tandem or IMSn–MSm applications.
Sources: en.wikipedia.org
The dry powder is typically held at -20 degrees Celsius or lower, protected from light and moisture. Allowing a sealed vial to reach room temperature before opening reduces condensation on its contents. Conditions stated on a supplier certificate of analysis take precedence over general guidance.
Mass spectrometry supplies an observed molecular mass that is compared with the calculated value for the tetrapeptide. Reversed-phase chromatography then separates the main peak from related impurities. Neither technique alone establishes residue order, so sequence-level confirmation may call for tandem mass spectrometry or amino acid analysis.
No single published figure applies, because stability depends on pH, concentration, temperature and sterility. Cold storage slows hydrolysis without halting it, and microbial growth is a separate concern in non-sterile solutions. Most laboratories rely on their own analytical checks rather than a fixed expiry period.
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.