A practical reference on Deamidation: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-07-31. Anything still debated is marked as such rather than presented as settled.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Free acid form of the tetrapeptide |
| Molecular mass | About 390.35 Da | Calculated monoisotopic value |
| Appearance | White to off-white powder | Typical lyophilized presentation |
| Solubility | Soluble in water | Also dissolves in buffered saline |
| Storage temperature | Minus 20 degrees Celsius | Dry, dark conditions; avoid repeated thawing |
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
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 residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
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 normal range for fasting blood sugar in people without diabetes is 70 to 99 mg/dL (3.9 to 5.5 mmol/L). The range for individuals considered to have prediabetes is 100 to 125 mg/dL (5.6 to 6.9 mmol/L). If the fasting blood sugar is greater than 126 mg/dL (7.0 mmol/L) on blood tests taken on separate occasions, individuals are considered to have diabetes. Another useful test that is usually done via a blood test is the measurement of blood HbA1c (hemoglobin A1c) levels. In the blood, there is a molecule called hemoglobin which carries oxygen to the cells. Glucose can attach itself to this molecule and if the blood glucose is consistently high, the value of the A1c will increase. This test, unlike the other tests, is measured as a percentage because the test measures the proportion of all the hemoglobin that has glucose attached. This test measures the average amount of blood sugar control over a period of about 3 months (90 days). In people without diabetes, the HbA1c level ranges from 4.0 to 5.7%. The range for people with prediabetes is 5.7 to 6.4%, and anything above 6.4% is considered diabetic range. Due to the HbA1c serving as an accurate indicator of overall glycemic control, regular 6 month laboratory testing of HbA1c (glycated hemoglobin) is recommended to gauge long-term control and allows for more information to then adjust a person's lifestyle as well as routine medication dosages in such cases. Optimal management of diabetes involves individuals measuring and recording their own blood glucose levels.
== H == HAART – hairy leukoplakia – half-life – HAM/TSP – Health Care Financing Administration (HCFA) – Health Resources and Services Administration (HRSA) – HELLP syndrome – helper T cells – helper/suppressor ratio (of T cells) – hematocrit – hematotoxic – hemoglobin – hemolysis – hemophilia – hepatic – hepatic steatosis – hepatitis – hepatitis C and HIV coinfection – hepatomegaly – herpes simplex virus 1 (HSV-1) – herpes simplex virus 2 (HSV-2) – herpes varicella zoster virus (VZV) – herpes viruses – highly active antiretroviral therapy (HAART) – histocompatibility testing – histoplasmosis – HIV disease – HIV prevention trials network (HPTN) – HIV set point – HIV vaccine trials network (HVTN) – HIV-1 – HIV-2 – HIV-associated dementia – HIV-related tuberculosis – HLA – Hodgkin's disease – holistic medicine – homology (biology) – hormone – host – host factors – HPTN – HPV – HRSA – HTLV-I – HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) – HTLV-II – human growth hormone (HGH) – human immunodeficiency virus type 1 (HIV-1) – human immunodeficiency virus type 2 (HIV-2) – human leukocyte antigens (HLA) – human papilloma virus (HPV) – human T cell lymphotropic virus type I (HTLV-I) – human T cell lymphotropic virus type II (HTLV-II) – humoral immunity – HVTN – hydroxyurea – hypergammaglobulinemia – hyperglycemia – hyperlipidemia – hyperplasia – hyperthermia – hypogonadism – hypothesis – hypoxia
The Litton detector was developed for sampling the light energy distribution in the rear focal-plane of a spherical lens for sampling geometric relationships and the spectral density distribution of objects recorded on film transparencies. The application of the Litton detector by Salzman et al. provided measurement at 32 small scattering angles between 0° and 30°, and averaging over a broad range of azimuthal angles as the most important angles are the forward angles for static light scattering. By 1980, Bartholi et al. had developed a new approach to measuring the scattering at discrete scattering angles by using an elliptical reflector to permit measurement at 30 polar angles over the range 2.5° ≤ θ ≤ 177.5° with a resolution of 2.1°. The commercialization of multiangle systems began in 1977 when Science Spectrum, Inc. patented a flow-through capillary system for a customized bioassay system developed for the USFDA. The first commercial MALS instrument incorporating 8 discrete detectors was delivered to S.C. Johnson and Son, by Wyatt Technology Company, in 1983, followed in 1984 with the sale of the first 15 detector flow instrument (Dawn-F) to AMOCO. By 1988, a three-dimensional configuration was introduced specifically to measure the scattering properties of single aerosol particles. At about the same time, the underwater device was built to measure the scattered light properties of single phytoplankton. Signals were collected by optical fibers and transmitted to individual photomultipliers.
Sources: en.wikipedia.org
Antagonism of the 5-HT3 receptor has been found to enhance the increase in brain serotonin levels produced by serotonin reuptake inhibition in animal studies. Whether or not the 5-HT3 receptor antagonism of vortioxetine likewise does this in humans or contributes to its clinical antidepressant efficacy is unclear. SSRIs and 5-HT1A receptor agonists often produce nausea as a side effect, whereas 5-HT3 receptor antagonists like ondansetron are antiemetics and have been found to be effective in treating SSRI-induced nausea. It was thought that the 5-HT3 receptor antagonism of vortioxetine would reduce the incidence of nausea relative to SSRIs. However, clinical trials found significant and dose-dependent rates of nausea with vortioxetine that appeared to be comparable to those found with the SNRI duloxetine. Vortioxetine has been found to slightly reduce oxytocin levels in rodents. Serotonin 5-HT1A receptor agonists can enhance oxytocin release, but vortioxetine shows 10- to 15-fold lower affinity for the serotonin 5-HT1A receptor in rodents compared to humans.
== Chemistry and mechanism of action == Teduglutide differs from natural GLP-2 by a single amino acid: an alanine is replaced with a glycine. This blocks breaking down of the molecule by dipeptidyl peptidase and increases its half-life from seven minutes (GLP-2) to about two hours, while retaining its biological actions. These include maintenance of the intestinal mucosa, increasing intestinal blood flow, reducing gastrointestinal motility and secretion of gastric acid.
== History == Justus von Liebig showed in 1829 that hippuric acid differed from benzoic acid and he named it, and in 1834 he determined its constitution, while in 1853 French chemist Victor Dessaignes (1800–1885) synthesized it by the action of benzoyl chloride on the zinc salt of glycine. It was also formed by heating benzoic anhydride with glycine, and by heating benzamide with monochloroacetic acid.
Sources: en.wikipedia.org
=== Treatment === When noma is detected early, its progression can be rapidly halted through basic hygiene, antibiotics, and improved nutrition. However, its physical effects are permanent and may require oral and maxillofacial surgery or reconstructive plastic surgery to repair. Treatments for noma in the acute stage include penicillin, sulfonamides, and other antibiotics. In all stages of noma, the World Health Organization encourages antibiotics, vitamin A supplements or other nutritional supplements, a high-protein diet, and proper hydration. The World Health Organization recommends using amoxicillin and metronidazole in tandem to treat stage I noma (acute necrotizing gingivitis), along with the use of chlorhexidine and hydrogen peroxide to clean the mouth and gums. For stage II noma (edema phase), stage III noma (acute/gangrenous stage), and stage IV noma (scarring phase), the WHO recommends either one of two therapies. The first therapy includes the concurrent use of amoxicillin, clavulanic acid, gentamicin, and metronidazole. The second option includes the concurrent use of ampicillin, gentamicin, and metronidazole. For both options, chlorhexidine mouthwash is advised. For stage III and IV noma, the use of ketamine, and honey are both given as options for dressing the lesions. Reconstruction is usually very challenging and should be delayed until full recovery (usually about one year following initial intervention).
=== Chile === In Chile, iced coffee is called café helado (iced coffee) and is popular in the summer. Café helado is composed of espresso or coffee powder. Ice cream is added to the coffee, as are sugary additives such as vanilla, cinnamon, or dulce de leche. Iced coffee is served during the summer at breakfast and at parties. Chilean iced coffee may be topped with whipped cream and chopped nuts.
Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing takes many forms, from grinding grain into raw flour to home cooking and complex industrial methods used in the making of convenience foods. Some food processing methods play important roles in reducing food waste and improving food preservation, thus reducing the total environmental impact of agriculture and improving food security. Food Processing Levels (FPL) are defined according to physical and chemical changes occurring during food treatments. FPL are required in processed food classifications, such as the Nova classification, to categorise processed foods according to their FPL for different purposes. Primary food processing is necessary to make most foods edible while secondary food processing turns ingredients into familiar foods, such as bread. Tertiary food processing results in ultra-processed foods and has been widely criticized for promoting overnutrition and obesity, containing too much sugar and salt, too little fiber, and otherwise being unhealthful in respect to dietary needs of humans and farmed animals.
10,000 protein-coding genes (~50% of all human genes) are expressed in the normal human pancreas. Less than 100 of these genes are specifically expressed in the pancreas. Similar to the salivary glands, most pancreas-specific genes encode for secreted proteins. Corresponding pancreas-specific proteins are either expressed in the exocrine cellular compartment and have functions related to digestion or food uptake such as digestive chymotrypsinogen enzymes and pancreatic lipase PNLIP, or are expressed in the various cells of the endocrine pancreatic islets and have functions related to secreted hormones such as insulin, glucagon, somatostatin and pancreatic polypeptide.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.
No naturally occurring free form of the peptide has been described. The four-amino-acid sequence can appear as a fragment within larger proteins, but that is not the same as the intact compound being present as a circulating molecule. Materials used in research are synthetic.
Purity is usually checked by reverse-phase high-performance liquid chromatography, which separates the target peptide from related impurities. Mass spectrometry is commonly used alongside it to confirm molecular mass. Some suppliers also provide amino acid analysis for additional sequence confirmation.
The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.