If you have been reading about Reversed-phase HPLC and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-09-28. Numbers and descriptions here follow the published literature rather than marketing material.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
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.
Reversed-phase high-performance liquid chromatography is the standard approach for assessing purity, usually with ultraviolet detection near 214 nm, where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the molecular mass and helps reveal truncation or deletion byproducts. Amino acid analysis can verify composition, and counterion content is sometimes measured because peptides purified with trifluoroacetic acid retain variable amounts of that salt. Purity figures reported without a stated method and detection wavelength are difficult to interpret.
| Property | Value | Notes |
|---|---|---|
| Storage temperature, solid | Approximately -20 C | Sealed, desiccated, protected from light |
| Typical identity method | Electrospray mass spectrometry | Protonated ion expected near 391 |
| Typical purity method | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Common synonyms | Epithalon, epithalone, AEDG | Spelling variants appear in supplier catalogues |
| Solution stability | Days at 2-8 C | Hydrolysis and deamidation limit shelf life |
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.
In 2022, Moore supported a bill to ban the possession and sale of privately made firearms in Maryland. He supports creating a firearms database to help law enforcement track guns used in crimes. In June 2022, Moore condemned the Supreme Court's ruling in New York State Rifle & Pistol Association, Inc. v. Bruen, calling it a "misguided and dangerous decision." He also opposed Governor Hogan's decision to suspend the state's "good and substantial reason" standard for obtaining a concealed carry permit following the ruling. In January 2023, Moore attended a Moms Demand Action rally in Annapolis, Maryland, where he said he would support the Gun Safety Act of 2023. The bill would increase the requirements and fees to obtain a handgun permit, strengthen safe storage requirements, and prohibit gun owners from carrying guns near schools, government property, construction areas, or entertainment venues, and from entering someone's property while carrying a firearm unless given permission by the owner. Moore signed the bill into law on May 16, 2023. That same day, the National Rifle Association of America (NRA) filed a lawsuit in federal court challenging the law's location restrictions. In September 2023, two days before the law was set to go into effect, U.S. District Judge George L. Russell III blocked sections of the bill restricting open carry near public demonstrations and private buildings, but upheld the remainder of the bill.
=== Health Services division === UPMC's Provider Services consists of an array of clinical capabilities that includes hospitals, specialty service lines (including transplantation, behavioral health, cancer care, children's health, women's health, and rehabilitation services among other centers, institutes, and services), contract services (emergency medicine, pharmacy, and laboratory), supporting foundations, captive insurance programs, and approximately 3,600 employed physicians with associated practices. Hospital activity is categorized in four distinct groups: 1. academic hospitals that provide comprehensive clinical services and specialty services and that are the primary academic and teaching centers; 2. community hospitals that provide core clinical services to suburban populations; 3. regional hospitals that provide clinical core services to broader areas of the Western Pennsylvania region; and 4. pre- and post-acute care capabilities that include a network of home health services (UPMC HomeCare) and a network of 15 senior living facilities (UPMC Senior Communities).
== History == Orexigen Therapeutics submitted a New Drug Application (NDA) for the combination to the FDA in March 2010. Having paid a fee under the Prescription Drug User Fee Act, Orexigen was given a deadline for the FDA to approve or reject the drug of January 2011. In December 2010, an FDA Advisory Committee voted 13–7 to approve Contrave and 11–8 to conduct a post-marketing cardiovascular outcomes study. Subsequently, on 2 February 2011, the FDA rejected the drug, and it was decided that an extremely large-scale study of the long-term cardiovascular effects of Contrave would be needed before approval could be considered. It was ultimately approved in the United States in 2014. In December 2014, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency endorsed the combination for licensure as an obesity medication when used alongside diet and exercise. Authorization was granted in March 2015. A review of Mysimba was completed by the CHMP in March 2025. In May 2015, Orexigen prematurely ended the trial that was intended to test whether naltrexone/bupropion increased the risk of major adverse cardiovascular events in obese patients with cardiovascular disease because an independent panel of experts said that the drug maker "inappropriately" compromised the trial by prematurely releasing interim data. The early data release reported a reduction in heart attacks, but that advantage was no longer observed when a more complete view of the data was analyzed.
== Structure and reactivity == κ-Bungarotoxin has a single polypeptide chain consisting of 66 amino acids. The overall weight of this chain is 7313 DA. Two single polypeptide chains can arrange together into a dimer. The subunit of the dimer consists of three main chain loops. These loops have a rotation of 178.6 degrees. Overall, κ-bungarotoxin has ten beta strands. This forms a six stranded antiparallel beta sheet configuration[8]. This is formed by three out of the five beta strands of each subunit of the dimer. Arg 34 is at the top of the central loop for each subunit. The outer strand of loop III is involved in an antiparallel arrangement. The κ-bungarotoxin dimer can make disulfide bonds, hydrogen bonds and van der Waals connections.
Inca technology includes devices, technologies and construction methods used by the Inca people of western South America (between the 1100s and their conquest by Spain in the 1500s), including the methods Inca engineers used to construct the cities and road network of the Inca Empire.
Sources: en.wikipedia.org
=== Relationship to land plants === Fossils of isolated spores suggest land plants may have been around as long as 475 million years ago (mya) during the Late Cambrian/Early Ordovician period, from sessile shallow freshwater charophyte algae much like Chara, which likely got stranded ashore when riverine/lacustrine water levels dropped during dry seasons. These charophyte algae probably already developed filamentous thalli and holdfasts that superficially resembled plant stems and roots, and probably had an isomorphic alternation of generations. They perhaps evolved some 850 mya and might even be as early as 1 Gya during the late phase of the Boring Billion.
Peppermint (Mentha × piperita) is a hybrid species of mint, a cross between watermint and spearmint. Indigenous to Europe and the Middle East, the plant is now widely spread and cultivated in many regions of the world. It is occasionally found in the wild with its parent species. Although the genus Mentha comprises more than 25 species, peppermint is the most widely used variant. While Western peppermint is derived from Mentha × piperita, Chinese peppermint, or bohe, is derived from the fresh leaves of M. haplocalyx. M. × piperita and M. haplocalyx are both recognised as plant sources of menthol and menthone, and are among the oldest herbs used for both culinary and medicinal products.
In 1889, Joseph von Mering and Oskar Minkowski excised the pancreas of a dog, which soon developed the symptoms of diabetes. According to some accounts, Minkowski was taught by his supervisor, Bernhard Naunyn, to test for sugar in urine whenever he noticed polyuria. According to some other accounts, a laboratory attendant pointed out that only the urine of the pancreatectomized dogs attracted flies, prompting the researchers to test for sugar. Ultimately, the pair tested for sugar in the urine and confirmed the connection with diabetes mellitus. This event is commonly credited as the formal discovery of a role for the pancreas in diabetes. While the researchers continued to work on obtaining a pancreatic extract, they were unable to obtain the presumed anti-diabetic substance. In 1893, Edouard Hédon in Montpellier conducted a pancreatectomy in two stages. In the first, he took out almost all of the pancreas, cutting off the supply of pancreatic juice entirely. He then left a small remnant of pancreas grafted under the dog's skin. The dog did not become diabetic until the remaining graft was also excised, leading Hédon to the conclusion that the pancreas must have two functions: digestion via an external secretion, and carbohydrate metabolism via some internal secretion that was released directly into the bloodstream. John MacLeod, among the Toronto group that later isolated and purified insulin for clinical use, cited this finding as the most convincing proof of an internal secretion in his 1913 book, Diabetes: Its Pathological Physiology.
Even though this reaction proceeds effectively at biological conditions, copper in this range of dosage is cytotoxic. Solutions to this problem have been presented, such as using water-soluble ligands on the copper to enhance cell penetration of the catalyst and thereby minimize the dosage needed, An analogous "RuAAC reaction" (catalyzed by ruthenium, instead of copper) allows for the selective production of 1,5-isomers.
=== Anti-DFS70 antibodies === Anti-DFS70 antibodies generate a dense fine speckled pattern in indirect immunofluorescence and are found in normals and in various conditions, but are not associated with a systemic autoimmune pathology. Therefore, they can be used to help to rule out such conditions in ANA positive individuals. A significant number of patients are diagnosed as systemic lupus erythematosus or undifferentiated connective tissue disease largely based on a positive ANA. In case no defined autoantibody can be detected (e.g. anti-ENA antibodies), the testing of anti-DFS70 antibodies is recommended to verify the diagnosis. Anti-DFS70 antibody tests are available as CE-marked tests. Until now, no FDA cleared assay is available.
Sources: en.wikipedia.org
== Society and culture == Some cultures regard the liver as the seat of the soul. In Greek mythology, the gods punished Prometheus for revealing fire to humans by chaining him to a rock where a vulture (or an eagle) would peck out his liver, which would regenerate overnight (the liver is the only human internal organ that actually can regenerate itself to a significant extent). Many ancient peoples of the Near East and Mediterranean areas practiced a type of divination called haruspicy or hepatomancy, where they tried to obtain information by examining the livers of sheep and other animals. In Plato, and in later physiology, the liver was thought to be the seat of the darkest emotions (specifically wrath, jealousy and greed) which drive men to action. The Talmud (tractate Berakhot 61b) refers to the liver as the seat of anger, with the gallbladder counteracting this. The Persian, Urdu, and Hindi languages (جگر or जिगर or jigar) refer to the liver in figurative speech to indicate courage and strong feelings, or "their best"; e.g., "This Mecca has thrown to you the pieces of its liver!". The term jan e jigar, literally "the strength (power) of my liver", is a term of endearment in Urdu. In Persian slang, jigar is used as an adjective for any object which is desirable, especially women. In the Zulu language, the word for liver (isibindi) is the same as the word for courage. In English the term 'lily-livered' is used to indicate cowardice from the medieval belief that the liver was the seat of courage. Spanish hígados also means "courage".
precipitate 1. (n.) A solid substance that separates from a liquid solution or diffuses out of a solid alloy during the process of precipitation. 2. (v.) To separate from another substance by forming a distinct, condensed solid phase.
== Function == The protein encoded by this gene contains a leucine-rich repeat and a death domain. This protein has been shown to interact with other death domain proteins, such as Fas (TNFRSF6)-associated via death domain (FADD) and MAP-kinase activating death domain-containing protein (MADD), and thus may function as an adaptor protein in cell death-related signaling processes. The expression of the mouse counterpart of this gene has been found to be positively regulated by the tumor suppressor p53 and to induce cell apoptosis in response to DNA damage, which suggests a role for this gene as an effector of p53-dependent apoptosis. Three alternatively spliced transcript variants encoding distinct isoforms have been reported. Besides its pro-apoptotic function it may also be involved in DNA repair as part of a protein complex formed together with the catalytic subunit of DNA-PK (DNA-PKcs) and caspase 2. Signaling pathways involving PIDD-C have been associated with the activation of NF-κB and the promotion of cell survival. Following DNA damage, PIDD-C relocates to the nucleus, where it forms a complex with RIP1 and the NF-kappa-B inhibitor kinase subunit gamma (NEMO, or IKBKG), collectively referred to as the 'NEMO-PIDDosome.' PIDD1 is also essential for translesion DNA synthesis (TLS), which enables DNA elongation across lesions in response to UV exposure.
For example, ammonia (NH3) is soluble in both water (aq) and the organic solvent trichloromethane (CHCl3) - two immiscible solvents. If ammonia is first dissolved in water, and then an equal volume of trichloromethane is added, and the two liquids shaken together, the following equilibrium is established:
Sources: en.wikipedia.org
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.
Reversed-phase chromatography with ultraviolet detection gives a purity percentage, while mass spectrometry confirms identity. Amino acid analysis checks the residue composition. Buyers typically request a certificate of analysis showing these measurements for the specific lot.
It is not authorised as a medicine in the United States or the European Union. Material is sold there as a research chemical or cosmetic ingredient. Some related short peptides are registered drugs in Russia, which is a distinct national situation rather than a general approval.
The powder is normally kept at −20 °C or below in a sealed, moisture-protected container. Letting the vial reach room temperature before opening helps prevent condensation on the contents.