Backbone hydrolysis 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 2026-01-08 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised and often hygroscopic |
| Solubility class | Freely soluble in water | Poor solubility in non-polar solvents |
| Typical storage temperature | -20 degrees Celsius or colder | Sealed, desiccated, protected from light |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Establishes purity and confirms mass |
| Common salt form | Trifluoroacetate or acetate | Counterion reported alongside purity values |
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.
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.
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.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
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.
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.
=== Project Texas === In response to security concerns of the United States government, TikTok has been working to silo privileged user data within the United States under oversight from the US government or a third party such as Oracle. Named Project Texas, the initiative focuses on unauthorized access, state influence, and software security. A new subsidiary, TikTok US Data Security Inc. (USDS), was created to manage user data, software code, back-end systems, and content moderation. It would report to the Committee on Foreign Investment in the United States (CFIUS), not ByteDance or TikTok, even for hiring practices. Oracle would review and spot check the data flows through USDS. It would also digitally sign software code, approve updates, and oversee content moderation and recommendation. Physical locations would be established so that Oracle and the US government could conduct their own reviews. The company has been engaged in confidential negotiations over the project with CFIUS since 2021 and submitted its proposal but received little response from the panel afterward. In March 2023, a former employee of the company said Project Texas did not go far enough and that a complete "re-engineering" would be needed. TikTok responded by saying that Project Texas already is a re-engineering of the app and that the former employee left in 2022 before the project specifications were finalized. Other former employees had their own takes on the situation. A data scientist said US user data were emailed to ByteDance workers in China to identify viewer interests.
Progesterone is a progestogen, or an agonist of the nuclear progesterone receptors (PRs), the PR-A, PR-B, and PR-C. In addition, progesterone is an agonist of the membrane progesterone receptors (mPRs), including the mPRα, mPRβ, mPRγ, mPRδ, and mPRϵ. Aside from the PRs and mPRs, progesterone is a potent antimineralocorticoid, or antagonist of the mineralocorticoid receptor, the biological target of the mineralocorticoid aldosterone. In addition to its activity as a steroid hormone, progesterone is a neurosteroid. Among other neurosteroid activities, and via its active metabolites allopregnanolone and pregnanolone, progesterone is a potent positive allosteric modulator of the GABAA receptor, the major signaling receptor of the inhibitory neurotransmitter γ-aminobutyric acid (GABA). The PRs are expressed widely throughout the body, including in the uterus, cervix, vagina, fallopian tubes, breasts, fat, skin, pituitary gland, hypothalamus, and in other areas of the brain. In accordance, progesterone has numerous effects throughout the body. Among other effects, progesterone produces changes in the female reproductive system, the breasts, and the brain. Progesterone has functional antiestrogenic effects due to its progestogenic activity, including in the uterus, cervix, and vagina. The effects of progesterone may influence health in both positive and negative ways. In addition to the aforementioned effects, progesterone has antigonadotropic effects due to its progestogenic activity, and can inhibit ovulation and suppress gonadal sex hormone production.
=== Taxi === Commercial taxi services and route taxis are widely used in Moscow. During the mid-2010s, service platforms such as Yandex Taxi, Uber, and Gett displaced many private drivers and small service providers; in 2015, these platforms serviced more than 50% of all taxi orders in the city. As of 2021, Russian technology company Yandex was testing self-driving taxis in Moscow.
Sources: en.wikipedia.org
==== Other ==== Many other Wildcats have met with success at the university. Alix Creek and Michelle Oldham won the NCAA Women's Doubles Tennis title in 1993, defeating Texas in the Final. Although surprising to some, the University of Arizona has a noteworthy history in ice hockey. The school's club hockey team, formerly known as the Icecats, won over 800 games between its inception in 1979 and 2011. The Ice Cats defeated Penn State for the National Collegiate Club Hockey National Championship in 1985. They also appeared in eight Final Fours ('84, '86, '87, '88, '91, '93, '94, '97) and ten Elite Eights. As of 2011, they are part of ACHA Division I, and are known formally as the Arizona Wildcats hockey team. Robert M. Tanita was a nationally ranked collegiate wrestler who reached the NCAA finals tournament as WAC champion in 1963. Three national championships for synchronized swimming were won in 1980, 1981, and 1984, though these championships were in the Association of Intercollegiate Athletics for Women, and not the NCAA. Along with winning three national championships in the pool for synchronized swimming, the Wildcats have also won their first NCAA Championship in men and women's swimming and diving for the seasons of 2007–2008. Topping off these weekends Frank Busch, the men and women's head coach, was named NCAA Swimming Coach of the Year. Arizona men became the first team to claim a first-time title since UCLA's win in 1982. Also, the men ended Texas and Auburn's winning streak since 1998.
== Medical uses == Chlorprothixene's principal indications are the treatment of psychotic disorders (e.g. schizophrenia) and of acute mania occurring as part of bipolar disorders. Other uses are pre- and postoperative states with anxiety and insomnia, severe nausea / emesis (in hospitalized patients), the amelioration of anxiety and agitation due to use of selective serotonin reuptake inhibitors for depression and, off-label, the amelioration of alcohol and opioid withdrawal. It may also be used cautiously to treat nonpsychotic irritability, aggression, and insomnia in pediatric patients. An intrinsic antidepressant effect of chlorprothixene has been discussed, but not proven. Likewise, it is unclear if chlorprothixene has genuine (intrinsic) analgesic effects. However, chlorprothixene can be used as co-medication in severe chronic pain. Also, like most antipsychotics, chlorprothixene has antiemetic effects.
=== Jewelry === In August 2025, within the course of a joint project with the European Commission monitoring online marketplaces such as Temu, AliExpress and Shein, the Latvian Consumer Rights Protection Centre, while testing a selection of best-selling jewelry goods, discovered extreme quantities of cadmium in 60% of the tested products. Some of the items were found to consist mostly of cadmium, at a purity of 80% or higher, in one case — a ring from AliExpress shaped like a snake — an impressive 92% cadmium alloy, evidencing that there is at least one jewelry manufacturer that has been using cadmium at some point as the primary material for its products and may still be doing so.
== Regenerated cellulose == Cellulose is soluble in several kinds of media, several of which are the basis of commercial technologies. These dissolution processes are reversible and are used in the production of regenerated celluloses (such as viscose and cellophane) from dissolving pulp. The most important solubilizing agent is carbon disulfide in the presence of alkali. Other agents include Schweizer's reagent, N-methylmorpholine N-oxide, and lithium chloride in dimethylacetamide. In general, these agents modify the cellulose, rendering it soluble. The agents are then removed concomitant with the formation of fibers. Cellulose is also soluble in many kinds of ionic liquids. The history of regenerated cellulose is often cited as beginning with George Audemars, who first manufactured regenerated nitrocellulose fibers in 1855. Although these fibers were soft and strong -resembling silk- they had the drawback of being highly flammable. Hilaire de Chardonnet perfected production of nitrocellulose fibers, but manufacturing of these fibers by his process was relatively uneconomical. In 1890, L.H. Despeissis invented the cuprammonium process – which uses a cuprammonium solution to solubilize cellulose – a method still used today for production of artificial silk. In 1891, it was discovered that treatment of cellulose with alkali and carbon disulfide generated a soluble cellulose derivative known as viscose. This process, patented by the founders of the Viscose Development Company, is the most widely used method for manufacturing regenerated cellulose products.
Sources: en.wikipedia.org
The 4n+3 chain of uranium-235 is commonly called the "actinium series" or "actinium cascade", from the first member known when it was named, actinium-227. This series terminates with lead-207, 7 alpha decays and 4 beta decays from uranium. In the early Solar System, this chain went back to 247Cm. This manifests itself today as variations in 235U/238U ratios, since curium and uranium have noticeably different chemistries and therefore partitioned differently. The total energy released from uranium-235 to lead-207, including the energy lost to neutrinos, is 46.40 MeV; from californium-251, 69.91 MeV.
In chemical reactors, the goal is to make components react with a high yield. In a homogeneous, first-order reaction, the probability that an atom or molecule will react depends only on its residence time:
== Circular economy == Recent research has begun to investigate the relationship between fermentation and creating a circular economy in effort to address the current climate crisis and the increasing demands for resources as the population grows. The production of fuels, materials, and other chemicals has led to a notable increase in greenhouse gasses and a subsequent increase in global temperatures. The current, linear economy relies heavily on fossil fuels and nonrenewable energy to produce chemicals and materials. In a circular economy, the use of renewable resources would be employed to produce chemicals; moreover, this type of economy focuses on reusing end-of-life chemicals and materials. Investigation into alternative biofuels and biomaterials has become increasingly popular with fermentation as a notable method. The primary source of biomass for fermentation is using biomass feedstocks which contain a mix of carbohydrates, proteins, oils and fats, and lignin. Carbohydrates such as sucrose and starch (sources include sugarcane, corn, and cassava) are the most commonly used substrate for fermentation; however, in the discussion of biofuels, there are concerns regarding land competition between food and fuel biomass. Attention has been turned towards second-generation biomass feedstock such as silvergrass or wood chips.
Sources: en.wikipedia.org
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.
Reversed-phase HPLC establishes purity and separation from related peptides, and mass spectrometry confirms the molecular mass. Amino acid analysis can verify residue composition. No single method proves identity on its own, so the results are read together.
Yes. Residual trifluoroacetate or acetate from purification adds mass and can shift the value obtained by certain assays. Purity figures are therefore meaningful only when the counterion form is stated. Reporting both peptide content and salt form gives a clearer picture.
It is a synthetic tetrapeptide built from alanine, glutamate, aspartate and glycine. The four residues are joined by standard peptide bonds, giving a linear chain rather than a branched structure.