aspartimide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-04-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
| 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 |
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
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.
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
（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.
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.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Rare but serious adverse effects found through postmarketing surveillance include prolonged erections, severe low blood pressure, myocardial infarction (heart attack), ventricular arrhythmias, stroke, increased intraocular pressure, and sudden hearing loss. In October 2007, the FDA announced that the labeling for all PDE5 inhibitors, including sildenafil, required a more prominent warning of the potential risk of sudden hearing loss.
The two substrates of this enzyme are D-glucose and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are glucono-δ-lactone, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is D-glucose:NADP+ 1-oxidoreductase. Other names in common use include nicotinamide adenine dinucleotide phosphate-linked aldohexose, dehydrogenase, NADP+-linked aldohexose dehydrogenase, NADP+-dependent glucose dehydrogenase, and glucose 1-dehydrogenase (NADP+).
The basic process, patented in 1922, is called the Bosch–Meiser urea process after its discoverers Carl Bosch and Wilhelm Meiser. The process consists of two main equilibrium reactions, with incomplete conversion of the reactants. The first is carbamate formation: the fast exothermic reaction of liquid ammonia with gaseous carbon dioxide (CO2) at high temperature and pressure to form ammonium carbamate ([NH4]+[NH2COO]−):
Sources: en.wikipedia.org
=== Detector === In GPC, the concentration by weight of polymer in the eluting solvent may be monitored continuously with a detector. There are many detector types available and they can be divided into two main categories. The first is concentration sensitive detectors which includes UV-VIS absorption, differential refractometer (DRI) or refractive index (RI) detectors, infrared (IR) absorption and density detectors. The second category is molecular weight sensitive detectors, which include low angle light scattering detectors (LALLS) and multi angle light scattering (MALS). The resulting chromatogram is therefore a weight distribution of the polymer as a function of retention volume. The most sensitive detector is the differential UV photometer and the most common detector is the differential refractometer (DRI). When characterizing copolymer, it is necessary to have two detectors in series. For accurate determinations of copolymer composition at least two of those detectors should be concentration detectors. The determination of most copolymer compositions is done using UV and RI detectors, although other combinations can be used.
As such, EMP therapy results in considerably stronger androgen deprivation than orchiectomy. Metabolites of EMP, including estramustine, estromustine, estradiol, and estrone, have been found to act as weak antagonists of the androgen receptor (EC50Tooltip half-maximal effective concentration = 0.5–3.1 μM), although the clinical significance of this is unknown. Extremely high levels of estradiol and estrone occur during EMP therapy. The estrogenic metabolites of EMP are responsible for its most common adverse effects and its cardiovascular toxicity. EMP has been described as having relatively weak estrogenic effects in some publications. However, it has shown essentially the same rates and degrees of estrogenic effects, such as breast tenderness, gynecomastia, cardiovascular toxicity, changes in liver protein synthesis, and testosterone suppression, as high-dose diethylstilbestrol and ethinylestradiol in clinical studies. The notion that EMP has relatively weak estrogen activity may have been based on animal research, which found that EMP had 100-fold lower uterotrophic effects than estradiol in rats, and may also not have taken into account the very high doses of EMP used clinically in humans. The mechanism of action of the cytostatic effects of EMP is complex and only partially understood. EMP is considered to mainly be a mitotic inhibitor, inhibiting mechanisms involved in the mitosis phase of the cell cycle.
In maggot debridement therapy, sterile, medical-grade larvae of the necrophagous fly Lucilia sericata are used to eliminate necrotic (dead) tissue from non-healing skin and soft-tissue wounds. This is important as dead tissue can facilitate bacterial growth, impede wound healing, and reduce the effectiveness of topical medications. Physicians may administer the fly larvae directly to skin and soft tissue wounds or indirectly within a sealed mesh bag. Larvae then debride the wound by digesting, liquefying and consuming the dead tissue. The US Food and Drug Administration (FDA) have cleared Lucilia sericata larvae for use as a "medical device" in the US to debride several types of wound including pressure ulcers, neuropathic foot ulcers, and nonhealing surgical wounds.
== History == The first 15 years of the EIP focused on establishing vaccination schedules and ensuring that poorer countries had a supply of vaccines. In 1974, only 5% of children in low-income countries and 21% of all children received basic vaccines. DTP3 coverage increased from 20% in 1982 to 76% in 1990. (DTP3 refers to the third shot of the DTP vaccine. DTP3 completion rates in one-year-olds is used as a proxy for infant vaccination completion rates.) The growth was fueled by Child Survival and Development Revolution initiated by Jim Grant in UNICEF. After the sharp increase in vaccination rates, the growth has slowed to a halt because the most of the remaining infants live in places where the cold chain for vaccine storage is unreliable. In response the EPI broadened its scope and introduced more vaccines (HepB, Hib, PCV) into schedules. This expands the spectrum of protection for kids with access to vaccines. The GAVI was founded in 2000, providing funding for expanding vaccine access in poorer countries. The DTP3 completion rate was 83% by 2010. Technical innovations such as the solar-powered refrigerator and the vaccine vial monitor played a large role in gaining the 7 percentage points. In the one-and-a-half decades after 2010, the EPI saw major achievements including the appearance and endorsement of rotavirus, HPV, and malaria vaccines. The rotavirus vaccine greatly reduced women and child mortality due to diarrhea; the HPV vaccine had already made a dent in the number of cervical cancer cases; and the malaria vaccine too has saved lives.
Sources: en.wikipedia.org
== Treatment in the future == N-terminal acetylation plays a larger role overall in cell homeostasis and changing one of the NATs has a large impact, mostly due to the vast number of substrates that are subjected to N-terminal acetylation. The mechanism and impact on the proteome level are much needed to be studied, to understand the molecular mechanisms underlying the phenotypes of the affected individuals. There could be many proteins involved in such mechanisms, and this needs to be studied to reveal new angles for improved treatment.
Based on this data, alogliptin was chosen for preclinical evaluation. In January 2007 alogliptin was undergoing the phase III clinical trial and in October 2008 it was being reviewed by the U.S. Food and Drug Administration.
=== Sequencing and synthesis === The sequence of the oligonucleotide selected using SELEX is determined with the help of DNA sequencing. This information is used for the synthesis of the oligonucleotide's enantiomer, the L-RNA aptamer, using L-nucleotides.
=== Walter Bennett === Dr. Walter Bennett (voiced by Harry S. Robins) is a Black Mesa scientist. He is seen in Half-Life: Blue Shift. In Blue Shift, Dr. Bennett is seen fixing a battery in Dr. Rosenberg's office, along with Dr. Simmons. The three scientists soon get it fixed with the help of Barney Calhoun, and they start their teleportation out of Black Mesa. The four successfully make it out of the facility, making Dr. Bennett one of the few known survivors of the incident. They open the gates and start their journey to the outside world with an SUV. Dr. Bennett is briefly mentioned in Half-Life: Opposing Force. As Adrian Shephard traverses within Sector E of Black Mesa, he enters a testing laboratory where Xen specimens were being experimented on prior to the Resonance Cascade. He opens up a transmission intended for Dr. Bennett, revealing a hologram of a scientist talking about the results of an experiment conducted on a Barnacle, which was one of the Xen creatures being examined. Following the transmission, Shephard takes a nearby Barnacle specimen that was intended for Dr. Bennett to experiment on before the Resonance Cascade. Dr. Bennett's final fate is unknown.
This enables the measurements of quadrupolar doublets for each nonequivalent deuterium atom. Thus reduces peak overlaps and provides more detailed information of hydrogen chemical environment. Mainstream uses of 2H-SNIF-NMR have been in source attribution, forensics and biosynthetic pathway studies. (See also Gray's section "Source attribution and Forensics") When measuring sugar compounds, a timesaving strategy is to convert them into ethanol through fermentation because 2H-SNIF NMR for ethanol is well established. Several studies have proved that hydrogen isotopes on the methyl and methylene position of the resulting ethanol is not affected by either fermentation rate or media. Another example is the study of monoterpenes. since the 1980s SNIF-NMR study of α-pinene has found large variations in DHR among its sites. Particularly ex-C2 position has a strong depletion (~-750‰), which was in disagreement with accepted biosynthetic mechanism (mevalonate mechanism) at that time, and lead to new development in pathways. More recently, Ina Ehlers published their work on the D6S/D6R ratios of glucose molecules. The stereochemical diteterium distribution was found to correlate to photorespiration/photosynthesis ratios. Photorespiration/photosynthesis ratios are driven by CO2 fertilization, thus this might lead to new proxies in reconstructing paleo-CO2 concentration.
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.
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.