If you have been reading about aspartimide 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.
Last reviewed on 2025-09-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
Identity is normally established by reversed-phase high-performance liquid chromatography combined with mass spectrometry, a pairing that separates components and confirms molecular mass at once. Purity is quoted as a percentage from the chromatogram, and figures above ninety-five percent are a frequent commercial specification. Amino acid analysis or sequencing supplies further confirmation when required. Because many short peptides behave similarly under chromatography, retention time alone does not establish sequence; the mass measurement is what separates one tetrapeptide from another, and certificates should report both.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
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.
| Property | Value | Notes |
|---|---|---|
| Sequence | Ala-Glu-Asp-Gly | Written in three-letter amino acid code |
| Single-letter code | AEDG | Form used in most catalogue entries |
| Typical purity specification | 95 percent or higher | Value read from the HPLC chromatogram |
| Storage, dry solid | Minus 20 degrees Celsius, desiccated | Sealed container, protected from light |
| Handling, solution | Divide into single-use portions | Limits losses from freeze-thaw cycling |
Reversed-phase high-performance liquid chromatography is the standard approach for assessing purity, usually with ultraviolet detection near 214 nm, where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the molecular mass and helps reveal truncation or deletion byproducts. Amino acid analysis can verify composition, and counterion content is sometimes measured because peptides purified with trifluoroacetic acid retain variable amounts of that salt. Purity figures reported without a stated method and detection wavelength are difficult to interpret.
Material sold for research use varies widely in documented quality. A useful verification package includes a certificate of analysis that states peptide content rather than only net weight, the chromatographic method and column used, and a mass spectrum consistent with the expected mass. Independent testing by a third-party laboratory is occasionally reported. Statements of identity resting only on a supplier label provide little assurance, and the gap between nominal mass and actual peptide content can be substantial once counterions and residual water are counted.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
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.
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.
The most widely cited claim is that epitalon activates telomerase and thereby extends telomere length. Supporting evidence comes largely from cultured human cells, where treatment was associated with increased telomerase activity and delayed replicative senescence. Telomerase activation is a biologically consequential effect, since the enzyme is largely silenced in most somatic cells. However, the route by which a short peptide would reach and act on the enzyme's regulatory machinery has not been established. Independent replication in human trials is scarce, so the link between cell-culture observations and whole-body aging remains an open question.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
We oppose so-called `harm reduction´ strategies as endpoints that promote the false notion that there are safe or responsible ways to use drugs. That is, strategies in which the primary goal is to enable drug users to maintain addictive, destructive, and compulsive behavior by misleading users about some drug risks while ignoring others. Such shortcomings arguably exist with some harm reduction measures, such as supervised injection facilities. These facilities provide users with the information and equipment necessary to avoid infection with diseases such as HIV, but leave them dependent on the black market. So users still face the health risk associated with the injection of impure street drugs and they still face the enormous financial strain of financing their addiction. In the case of heroin-assisted treatment however, users are provided with a form of pharmaceutical-grade heroin injection solution which doctors consider fit for injection. And as doctors refrain from drastic changes in dose and provide post-injection monitoring, overdoses are rare and can be quickly treated with opioid antagonists like naloxone. Thus, patients in heroin-assisted treatment are relieved from the major complex of problems that defines illicit heroin use. Synthetic heroin taken under the aforementioned conditions is not neurotoxic and has few long-term side effects beside constipation and dependency.
== Medical uses == Mepitiostane is used as an antiestrogen and antineoplastic agent in the treatment of breast cancer. It is also used as an AAS in the treatment of anemia of renal failure. A series of case reports have found it to be effective in the treatment of an estrogen receptor (ER)-dependent meningiomas as well.
The FDA alerted medical practitioners that it had received nine additional reports of the same type and requested all health care professionals to report any such cases to the agency’s MedWatch program, or to their respective pharmaceutical manufacturers. The FDA subsequently received over a hundred additional reports of valvular heart disease in people taking fen-phen, fenfluramine alone, or dexfenfluramine alone. The FDA requested that the manufacturers of fenfluramine and dexfenfluramine stress the potential risk to the heart in the drugs' labeling and in package inserts. The FDA continued to receive reports in 1997 of valvular heart disease in people who had taken these drugs. This disease typically involves the aortic and mitral valves. After reports of valvular heart disease and pulmonary hypertension, primarily in women who had been undergoing treatment with fen-phen or (dex)fenfluramine, the FDA requested its withdrawal from the market in September 1997. The action was based on findings from doctors who had evaluated people taking these two drugs with echocardiograms, a procedure that can test the functioning of heart valves. The findings indicated that approximately 30 percent of people who had taken the combination for up to 24 months had abnormal echocardiograms, even though they had no symptoms. This percentage of abnormal test results was much higher than would be expected from a sample of the population who had not been exposed to either fenfluramine or dexfenfluramine.
=== 2010s === In 2010, Grace received approval from the U.S. Bankruptcy Court for the merger with Synthetec, which is a company that had developed and manufactured amino acid and peptide products as well as proprietary custom chiral intermediates primarily for the pharmaceutical industry. In 2014, the Grace bankruptcy process terminated. However, some legal procedures continued into the next decade. In February 2016, Grace completed the corporate spin-off of GCP Applied Technologies, which was also as a public trading corporation on the NYSE. Grace shareholders receive GCP stock on 1:1 ratio. GCP Applied Technologies consisted of the concrete admixture and related products company Grace Construction Products (GCP) and Darex, a packaging technologies business unit. In July 2016, Grace acquired the global polyolefin catalysts business unit from BASF.
Rémi Goulet (born 1997) is a Canadian film and television actor from Lavaltrie, Quebec, best known for his regular supporting role as Benji, the younger brother of protagonist Chuck, in the television series Pour toujours, plus un jour. He began his career as a child actor, with roles in the television series 30 vies and Tactik, and the film The Pee-Wee 3D: The Winter That Changed My Life (Les Pee-Wee 3d: L'hiver qui a changé ma vie). He had his first leading role in the 2019 film Living 100 MPH (Vivre à 100 milles à l'heure), playing a semi-fictionalized version of filmmaker Louis Bélanger. In 2020, he starred in the film The Marina (La Marina). In 2023, he was announced as playing Gilles Villeneuve in Villeneuve: The Rise of a Legend (Villeneuve : l'ascension d'une légende), which premiered as the closing film of the 2026 Toronto International Film Festival.
Sources: en.wikipedia.org
Cysteine (; symbol Cys or C) is a semiessential proteinogenic amino acid with the formula HS−CH2−CH(NH2)−COOH. The thiol side chain in cysteine enables the formation of disulfide bonds, and often participates in enzymatic reactions as a nucleophile. Cysteine is chiral, but both D- and L-cysteine are found in nature. L‑Cysteine is a protein monomer in all biota, and D-cysteine acts as a signaling molecule in mammalian nervous systems. Cysteine is named after its discovery in urine, which comes from the urinary bladder or cyst, from Greek κύστις kýstis, "bladder". The thiol is susceptible to oxidation to give the disulfide derivative cystine, which serves an important structural role in many proteins. In this case, the symbol Cyx is sometimes used. The deprotonated form can generally be described by the symbol Cym as well. When used as a food additive, cysteine has the E number E920. Cysteine is encoded by the codons UGU and UGC.
== History == Coiled-coil research began in 1953 when Dr. Francis Crick first reported on the theory behind the packing formation of α-helices in fibrous proteins at the time, which he proposed to consist of alpha helices composed of heptad repeats, or seven-residue repeats (a-b-c-d-e-f-g), whereby 2 or more alpha helices twist around each other similar to the strands of a rope. In 1972, Dr. Robert Hodges and his colleagues confirmed Dr. Crick's hypothesis upon sequencing tropomyosin, further discovering that the heptad repeat consists of two hydrophobic residues at the a and d positions, which stabilize coiled coils and are their basis for formation. This confirmation formed the basis for designing engineered coiled-coil proteins to further investigate and better understand coiled-coil interactions, structures, functions, oligomerization, and other properties. Later in 1991, Dr. O'Shea and colleagues obtained the first high-resolution image of a two-stranded coiled-coil at a resolution of 1.8Å. Dr. Hodges was the first to suggest the use of coiled coils in a drug delivery system in 1996 when he proposed a two-stage targeting and delivery system based on heterodimerization, whereby a drug would be conjugated to chain 1 and an antibody would be conjugated to chain 2, such that chains 1 and 2 would form a heterodimeric coiled coil.
== Biosynthesis == 2,5-DKPs are synthesized by a variety of organisms including humans. In general, they arise by the action of a tRNA-dependent cyclodipeptide synthases, a type of enzyme responsible for creating a cyclic amide linkage between two peptides. The enzymes cyclodipeptide oxidase and S-adenosyl-methionine-dependent O/N methyltransferases act in tandem to chemically modify cyclic dipeptides.
== Medications == As of 2015, there were eight FDA-approved SNRIs in the United States, with venlafaxine being the first drug to be developed in 1993 and levomilnacipran being the latest drug to be developed in 2013. The drugs vary by their other medical uses, chemical structure, adverse effects, and efficacy.
== Drug history == The discovery of paclitaxel began in 1962 as a result of a NCI-funded screening program. A number of years later it was isolated from the bark of the Pacific yew, Taxus brevifolia, hence its name "taxol". The discovery was made by Monroe E. Wall and Mansukh C. Wani at the Research Triangle Institute, Research Triangle Park, North Carolina, in 1971. These scientists isolated the natural product from the bark of the Pacific yew tree, determined its structure and named it "taxol", and arranged for its first biological testing. The compound was then developed commercially by BMS, who had the generic name assigned as "paclitaxel".
Sources: en.wikipedia.org
Using fundamental principles established by IUPAC, the delta (Δ) system for lipid notation was developed by researchers within the mid-20th century, to address the need for distinction between fatty acids with the same acyl chain length but different double bond positions. Thus, the Δ system defines the position of double bonds by virtue of the carboxyl (–COOH) carbon using the general formula: C:DΔy where C is the total number of carbons, D is the number of double bonds, and Δy indicates the position of each double bond, counting from the –COOH end of the fatty acid. Unlike the omega nomenclature system, each double bond of the fatty acid must be described in the delta system.
Bis(trimethylsilyl)acetamide (BSA) is an organosilicon compound with the formula MeC(OSiMe3)NSiMe3 (Me = CH3). It is a colorless liquid that is soluble in diverse organic solvents, but reacts rapidly with moisture and solvents containing OH and NH groups. It is used in analytical chemistry to increase the volatility of analytes, e.g., for gas chromatography. It is also used to introduce the trimethylsilyl protecting group in organic synthesis. A related reagent is N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA).
=== Methodology === Most tests employ a monoclonal antibody, which is specific to the β-subunit of hCG (β-hCG). This procedure is employed to ensure that tests do not make false positives by confusing hCG with LH and FSH. (The latter two are always present at varying levels in the body, whereas the presence of hCG almost always indicates pregnancy.) Many hCG immunoassays are based on the sandwich principle, which uses antibodies to hCG labeled with an enzyme or a conventional or luminescent dye. Pregnancy urine dipstick tests are based on the lateral flow technique.
== Future == Further advances in aquasome research require additional investigation of their in vivo drug release and targeting. Applications such as delivery of dithranol for the treatment of psoriasis and oral delivery of bromelain for the treatment of inflammatory diseases such as cancer show promising results in vitro and ex vivo. However, such applications have been unexplored in vivo, limiting their clinical use. Applications using aquasomes as carriers of hemoglobin, vaccines, and insulin have been tested in vivo in small animal models such as rats, mice, and rabbits, but current literature lacks in vivo testing in more advanced animal models, preventing their use as treatments for human conditions. Aquasomes are promising drug delivery mechanisms due to their ability to stabilize and transport a variety of substrates while allowing for controlled drug release. Prior to expanding the clinical applications of aquasomes, the gap existing in current literature will need to be filled by further investigating immune clearance of aquasomes, exploring additional surface modifications such as PEGylation, and expanding in vivo drug testing.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is run alongside mass spectrometry. The chromatogram separates components and gives a purity figure, while the mass spectrum confirms that the measured molecular mass matches the expected sequence. Neither measurement on its own is treated as sufficient.
Long-term holding is usually at minus twenty degrees Celsius in a sealed, desiccated container. A refrigerator is adequate for short intervals before use. Light exposure is normally avoided as well. Allowing a cold container to warm before opening reduces moisture condensation on the contents.
Repeated cycles are generally avoided. Each freeze and thaw can promote aggregation or loss of peptide to container surfaces, which reduces the amount available for later work. Dividing a solution into single-use portions at the outset is the usual way to limit this problem.
Sealed lyophilised powder is normally kept at minus twenty degrees Celsius or below, away from light and moisture. Vials are allowed to reach room temperature before opening to limit condensation. Repeated warming and cooling of the same vial is discouraged.