This is a working overview of lyophilised powder, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-04 and is reviewed periodically as new material appears.
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.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
| 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 |
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.
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.
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.
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.
Typical storage for the lyophilized powder is −20 °C or lower, in a sealed container protected from light and moisture. Hygroscopic material should be allowed to equilibrate to room temperature before the vial is opened, which limits condensation on the contents. Working solutions are commonly divided into single-use aliquots and frozen to avoid repeated freeze-thaw cycles. Dilute solutions are more prone to adsorption onto plastic surfaces and to loss during filtration, so procedures that minimize transfers and use low-binding labware are preferable.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
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.
The magnetic mass separators are able to separate isobars by mass number, however they are unable to sort isotopes of the same mass. If an experiment requires a higher degree of chemical purity, it will need the beam to have an additional separation, by proton number. RILIS provides this separation by using step-wise resonance photo-ionisation, involving precisely tuned laser wavelengths matched exactly to a specific element's successive electron transition energies. Ionisation will only occur of the desired element, and the other elements within the ion-source will remain unchanged. This process of laser ionisation takes place in a hot metal cavity to provide the spatial confinement needed for the atomic vapour to be illuminated. A high frequency laser system is needed to ionise the atom before it leaves the cavity. All in all, the ISOLDE facility provides 1300 isotopes from 75 elements in the periodic table.
Gingras research focuses on the development of experimental and bioinformatics approaches for functional proteomics, with a focus on protein-protein and proximity interactions. She applies these tools to the study of signaling pathways in health and disease and in mapping the physical organization of the dynamic proteome. Some of her work focuses on the consequence of disease-associated mutations on the interactions established by proteins. In addition to proteomics, Gingras laboratory has interest in studying human protein phosphatase and their systematic interactions and has now expanded into the field of systems biology.
Prior to the development of intradialytic parenteral nutrition in the late 20th century, nutritional management of patients receiving dialysis primarily relied on dietary counselling, liberalized renal diets, and oral nutritional supplements; however, protein–energy wasting (PEW) remained common among patients undergoing maintenance hemodialysis. Efforts to supplement nutritional intake by providing nutrients during the dialysis procedure were attempted. As a result, IDPN became an established therapy to threat malnourished CKD stage 5 dialysis patients in the early 1990s. Generally, the patients received a set formulation containing standard amounts of dextrose, amino acids and lipids regardless of the patient's weight, dialysis time, and complicating co-morbid conditions.
Zenobi-Wong works in the area of tissue engineering, in particular for cartilage regeneration. She develops functional biomaterials which mimic the extracellular matrix. The biofabrication techniques used to develop these materials include electrospinning, casting, two-photon polymerization and bioprinting. Zenobi-Wong holds four licensed patents in the fields of tissue engineering, tissue engineering techniques, and gene expression assays. She was one of the originators of the MSc Biomedical Engineering program at ETH Zürich, and developed several graduate level courses in tissue engineering and biomedical engineering. Zenobi-Wong currently serves as President of the Swiss Society for Biomaterials and Regenerative Medicine, and as secretary general of the International Society of Biofabrication. ETH Zürich Department of Health Sciences and Technology - Tissue Engineering and Biofabrication Group Marcy Zenobi-Wong publications indexed by Google Scholar
ASBMB hosts and sponsors numerous meetings each year. The annual meeting is held each April in conjunction with the Experimental Biology meeting. Additionally, themed special symposia are organized throughout the year. The society also produces webinars throughout the year focused on topics related to scientific research, professional development and education. The society offers twenty-five different awards, grants, and scholarships.
Sources: en.wikipedia.org
Isoforms I, III, and VIII are also stimulated by Ca2+/calmodulin. Isoforms V and VI are inhibited by Ca2+ in a calmodulin-independent manner. Isoforms II, IV and IX are stimulated by alpha subunit of the G protein. Isoforms I, V and VI are most clearly inhibited by Gi, while other isoforms show less dual regulation by the inhibitory G protein. Soluble AC (sAC) is not a transmembrane form and is not regulated by G proteins or forskolin, instead acts as a bicarbonate/pH sensor. It is anchored at various locations within the cell and, with phosphodiesterases, forms local cAMP signalling domains. In neurons, calcium-sensitive adenylyl cyclases are located next to calcium ion channels for faster reaction to Ca2+ influx; they are suspected of playing an important role in learning processes. This is supported by the fact that adenylyl cyclases are coincidence detectors, meaning that they are activated only by several different signals occurring together. In peripheral cells and tissues adenylyl cyclases appear to form molecular complexes with specific receptors and other signaling proteins in an isoform-specific manner.
The Edman degradation is an alternative method for peptide sequencing that cleaves amino acid residues from the N-terminus of a peptide. In 1950 Edman designed a reaction with phenylthiocyanate (the idea for which was borrowed from a 1927 study by Bergmann, Kann and Miekeley ) to give phenylthiocarbamyl peptides followed by hydrolysis under relatively mild conditions to cleave N-terminal amino acid as phenylthiohydantoin. Phenylthiohydantoin is stable enough to undergo various sequencing procedures such as those which involve chromatography and mass spectrometry. This was an improvement on an earlier method proposed by Abderhalden and Brockmann in 1930 that demonstrated N-terminal amino acid conversion to a hydantoin under stronger hydrolytic conditions, where some cleavage of the residual peptide proved problematic. The primary advantage the Edman degradation has over the Bergmann degradation is the ease with which the residual peptide can re-enter the process due to retention of its structure throughout sequential cleaving. Repetition of the Bergmann degradation is presumably not as straightforward, as the remaining peptide is in amide form.
The Oddo–Harkins rule holds that elements with even atomic numbers are more common than those with odd atomic numbers, with the exception of hydrogen and beryllium. This rule argues that elements with odd atomic numbers have one unpaired proton and are more likely to capture another, thus increasing their atomic number. In elements with even atomic numbers, protons are paired, with each member of the pair offsetting the spin of the other, enhancing stability. All the alkali metals have odd atomic numbers and they are not as common as the elements with even atomic numbers adjacent to them (the noble gases and the alkaline earth metals) in the Solar System. The heavier alkali metals are also less abundant than the lighter ones as the alkali metals from rubidium onward can only be synthesised in supernovae and not in stellar nucleosynthesis. Lithium is also much less abundant than sodium and potassium as it is poorly synthesised in both Big Bang nucleosynthesis and in stars: the Big Bang could only produce trace quantities of lithium, beryllium and boron due to the absence of a stable nucleus with 5 or 8 nucleons, and stellar nucleosynthesis could only pass this bottleneck by the triple-alpha process, fusing three helium nuclei to form carbon, and skipping over those three elements.
The orthologues and homologues of TMEM261 are limited to vertebrates, its oldest homologue dates to that of the cartilaginous fishes which diverged from Homo sapiens 462.5 million years ago. The protein primary structure of TMEM261 shows higher overall conservation in mammals, however high conservation of the domain of unknown function (DUF4536) to the C-terminus region is seen in all orthologues, including distant homologues. The protein structure of TMEM261 shows conservation across most orthologues. TMEM261 has no known paralogs. PubMed NCBI gene record GeneCards UCSC Genome Browser Expasy Bioinformatics Resource Portal SDSC Biology Workbench Uniprot HUGO Archived 2015-09-24 at the Wayback Machine
Chlorella vulgaris is a species of green microalga in the division Chlorophyta. This unicellular alga was discovered in 1890 by Martinus Willem Beijerinck as the first microalga with a well-defined nucleus. It is the type species of the genus Chlorella. It is found in freshwater and terrestrial habitats, and has a cosmopolitan distribution. Chlorella vulgaris has a number of potential applications in science, such as biofuel, livestock feed, and wastewater treatment. Beginning in the 1990s, German scientists noticed the high protein content of C. vulgaris and began to consider it as a new food source. Japan is currently the largest consumer of Chlorella, both for nutritional and therapeutic purposes, and it is used as a dietary supplement or protein-rich food additive in several countries worldwide. C. vulgaris is a green eukaryotic microalga. The cells are 4–10 μm in diameter, and are spherical. The chloroplast (chromatophore) is pea-green in color and cup-shaped, with a single pyrenoid.
Sources: en.wikipedia.org
Problems with mRNA stability have been identified in viral genomes, cancer cells, and various diseases. Research shows that many of these problems arise because of faulty ARE function. Deficiency of the ZFP36 family show that ZFP36 ARE binding proteins are critical regulators of T cell homeostasis and autoimmunity. Deficient mice have also indicated a protective role for ZFP36 ARE binding proteins via regulating cytokine levels in the thymic microenvironment, thereby preventing thymic involution. Additional potential problems have been listed below:
In 1974, GM offered driver and passenger airbags as optional equipment on large Cadillacs, Buicks, and Oldsmobiles. In 1976, the crash test dummy Hybrid III was introduced to assess the impacts of car collisions. It represented the 50th percentile male standing at approximately 5' 9" tall and weighing 78 kg (171 lbs). In 1979, NHTSA began crash-testing popular cars and publishing the results, to inform consumers and encourage manufacturers to improve the safety of their vehicles. Initially, the US NCAP (New Car Assessment Program) crash tests examined compliance with the occupant-protection provisions of FMVSS 208. Over the subsequent years, this NHTSA program was gradually expanded in scope.
Commercial availability varies by country. Approved systems in various countries, described further below, include MiniMed 670G or 780G, Tandem's Control-IQ, Omnipod 5, CamAPS FX, and Diabeloop DBLG1. In September 2016, the FDA approved the Medtronic MiniMed 670G, which was the first approved hybrid closed loop system. The device automatically adjusts a patient's basal insulin delivery. It is made up of a continuous glucose monitor, an insulin pump, and a glucose meter for calibration. It automatically functions to modify the level of insulin delivery based on the detection of blood glucose levels by continuous monitor. It does this by sending the blood glucose data through an algorithm that analyzes and makes the subsequent adjustments. The system has two modes. Manual mode lets the user choose the rate at which basal insulin is delivered. Auto mode regulates basal insulin levels from the CGM readings every five minutes.
Aside from the 22 proteinogenic amino acids, many non-proteinogenic amino acids are known. These either are not found in proteins (for example carnitine, GABA, ornithine) or are not produced directly and in isolation by standard cellular machinery. For example, hydroxyproline is synthesized from proline, and selenomethionine is produced by metabolic modification of methionine. Non-proteinogenic amino acids that are found in proteins are formed by post-translational modification. Such modifications can also determine the localization of the protein, e.g., the addition of long hydrophobic groups can cause a protein to bind to a phospholipid membrane. Examples:
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.
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.