This is a working overview of certificate of analysis, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-07-28 and is reviewed periodically as new material appears.
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.
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 | Derived from the four-residue sequence |
| Molar mass | About 390.35 g/mol | Free peptide, counter-ion not included |
| Appearance | White to off-white powder | Lyophilised solid from aqueous solution |
| Water solubility | Freely soluble | Short, polar peptide chain |
| Common synonyms | AEDG; epithalone | Catalogues use the names interchangeably |
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
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 sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
== Personal life == Kahn is married to Susan Becker Kahn, also formerly of Louisville. They have two children. Stacy Anne Kahn is a pediatric gastroenterologist at the Boston Children's Hospital. Jeffrey Adam Kahn is managing partner of Continuum Search based in Denver, Colorado. His brother Arnold Kahn was emeritus professor of developmental biology of the University of California San Francisco.
=== Phytochemicals === Polyphenol phytochemicals present in the fruit, seeds, and leaves are being investigated for their potential biological activities. Major anthocyanins in blackcurrant pomace – delphinidin-3-O-glucoside, delphinidin-3-O-rutinoside, cyanidin-3-O-glucoside, and cyanidin-3-O-rutinoside, which are retained in the juice concentrate – are among other polyphenols.
=== Binding sequence elution and amplification === Once the oligonucleotide library has been incubated with target for sufficient time, unbound oligonucleotides are washed away from immobilized target, often using the incubation buffer so that specifically bound oligonucleotides are retained. With unbound sequences washed away, the specifically bound sequences are then eluted by creating denaturing conditions that promote oligonucleotide unfolding or loss of binding conformation including flowing in deionized water, using denaturing solutions containing urea and EDTA, or by applying high heat and physical force. Upon elution of bound sequences, the retained oligonucleotides are reverse-transcribed to DNA in the case of RNA or modified base selections, or simply collected for amplification in the case of DNA SELEX. These DNA templates from eluted sequences are then amplified via PCR and converted to single stranded DNA, RNA, or modified base oligonucleotides, which are used as the initial input for the next round of selection.
Sources: en.wikipedia.org
Theater was introduced in Colombia during the Spanish colonization in 1550 through zarzuela companies. Colombian theater is supported by the Ministry of Culture and a number of private and state owned organizations. The Ibero-American Theater Festival of Bogotá is the cultural event of the highest importance in Colombia and one of the biggest theater festivals in the world. Other important theater events are: The Festival of Puppet The Fanfare (Medellín), The Manizales Theater Festival, The Caribbean Theatre Festival (Santa Marta) and The Art Festival of Popular Culture "Cultural Invasion" (Bogotá). Although the Colombian cinema is young as an industry, more recently the film industry was growing with support from the Film Act passed in 2003. Many film festivals take place in Colombia, but the two most important are the Cartagena Film Festival, which is the oldest film festival in Latin America, and the Bogotá Film Festival. Some important national circulation newspapers are El Tiempo and El Espectador. Television in Colombia has two privately owned TV networks and three state-owned TV networks with national coverage, as well as six regional TV networks and dozens of local TV stations. Private channels, RCN and Caracol are the highest-rated. The regional channels and regional newspapers cover a department or more and its content is made in these particular areas. Colombia has three major national radio networks: Radiodifusora Nacional de Colombia, a state-run national radio; Caracol Radio and RCN Radio, privately owned networks with hundreds of affiliates.
== Product development == Zealand Pharma does not promote and sell products in the market themselves, however, they form partnerships with several international pharmaceutical companies, who are responsible for placing the products on the market. Zealand Pharma is mostly known and recognized for the diabetes medication Lyxumia, which has been developed in collaboration with the French pharmaceutical company Sanofi. Since 2014, Zealand Pharma has collaborated with the coronary care unit at Rigshospitalet in Copenhagen developing the medication Danegaptid, which should serve the purpose of preventing injuries in the tissue of the heart, frequently seen among angioplasty patients. Furthermore, they are developing several orphan drugs with government assistance. Because of the acquisition of the Canadian Encycle Therapeutics, Zealand Pharma now also possesses the right to develop and sell the pre-clinical candidate medication ET3764, which is also being developed for the treatment of diseases of the alimentary tract.
Brain-specific angiogenesis inhibitor InterPro: IPR008077 BAI1; BAI2; BAI3 CD97 antigen InterPro: IPR003056 CD97 EMR hormone receptor InterPro: IPR001740 CELSR1; CELSR2; CELSR3; EMR1; EMR2; EMR3; EMR4 GPR56 orphan receptor InterPro: IPR003910 GPR56; GPR64; GPR97; GPR110; GPR111; GPR112; GPR113; GPR114; GPR115; GPR123; GPR125; GPR126; GPR128; GPR133; GPR144; GPR157 Latrophilin receptor InterPro: IPR003924 ELTD1; LPHN1; LPHN2; LPHN3 Ig-hepta receptor InterPro: IPR008078 GPR116
Sources: en.wikipedia.org
Several other designers subsequently joined the project in September 1999, with collective experience from the development of Daikatana, Quake II, Doom and Shadow Warrior. In the subsequent two months, media releases displaying a variety of screenshots were unveiled. The game was released on November 19, 1999. Gearbox later released a multiplayer update in May 2000, adding a capture the flag mode, along with various items to accompany the new mode. Opposing Force was later released on Valve's Steam content delivery system. Opposing Force was published as part of Sierra's Half-Life: Generation compilation in 2002, and as part of Valve and Electronic Arts' Half-Life 1: Anthology on September 26, 2005.
where R0 is the isotope ratio in the initial water vapor, Rr is the isotope ratio in the remaining water vapor after some condensation, f is the fraction of water vapor remaining in the air, and α is the liquid-vapor equilibrium fractionation factor (α=1+ε). The isotopic composition of the resulting precipitation (Rp) can be derived from the composition of the remaining vapor:
=== Powdered egg whites === Egg white can be dried alone for better foaming. The result is egg white powder. The ingredient called egg white protein is virtually identical to egg white powder, as no additional step is employed to separate the protein in egg white from other components before drying. Dried egg white products often have their foaming ability compromised by the inadvertent inclusion of egg yolk. Adding phospholipase A2 appears to break down the contaminant and restore the foaming power.
The Bloomin' Onion is a signature Outback item, though it is not an Australian item and is not typically sold in Australia apart from at this chain. It is a 1 pound (500 g) onion cut to 'bloom' open, breaded, deep-fried and served with mayonnaise-horseradish sauce. Other restaurants offer items similar to the Bloomin' Onion, as in Chili's Awesome Blossom (discontinued), Texas Roadhouse's Cactus Blossom, and Lone Star Steakhouse & Saloon's Texas Rose. Many of the Bloomin' Onions have come under fire for high-calorie counts, sometimes going over 1,500 calories.
Sources: en.wikipedia.org
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.
The name derives from epithalamin, a pineal gland extract studied in the former Soviet Union. Researchers proposed that short fragments of that extract carried the biological activity of interest.
No major regulatory agency has approved it as a medicine. It is handled as a research chemical, and products sold under this name are not standardised drugs with defined clinical labelling.
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.