The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-03. Anything still debated is marked as such rather than presented as settled.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
=== Part One === The first part of the film was created by Toronto-based David and Ian Purchase, the two of whom are collectively referred to as the Purchase Brothers. Before Escape from City 17, the Purchase Brothers had directed several commercials, including one for Coca-Cola. David contended that they worked as commercial directors in order to support their independent projects. Both being fans of the Half-Life series, the two decided to start Escape from City 17 as a way "to showcase and promote their talents further, and experiment with several post-production techniques they had developed." The two had a budget of Can$500; the computer equipment and software employed for the development of the film belonged to the Purchase Brothers from previous projects. According to David, the money was spent on the live-action elements of the film, saying that "the costumes, and used/broken airsoft guns made up the bulk of the budget." The two had no crew to support them, and were not paid for their work. Many of the elements of the film, such as the background, the Citadel, and the gunships, were extracted from Half-Life 2. The elements were then "graphically enhanced, and incorporated into the live action with a lot of complicated tracking and rotoscoping." The background used for the film's opening scene is the panorama of Riga. The "main set" of Part One was filmed at a trainyard with "active security." This made filming the short difficult, as the Purchase Brothers "tend not to get permits" to use the trainyard for the film.
(CH2CH2)O + HCl → HO–CH2CH2–Cl The reaction with these acids competes with the acid-catalyzed hydration of ethylene oxide; therefore, there is always a by-product of ethylene glycol with an admixture of diethylene glycol. For a cleaner product, the reaction is conducted in the gas phase or in an organic solvent. Ethylene fluorohydrin is obtained differently, by boiling hydrogen fluoride with a 5–6% solution of ethylene oxide in diethyl ether. The ether normally has a water content of 1.5–2%; in absence of water, ethylene oxide polymerizes. Halohydrins can also be obtained by passing ethylene oxide through aqueous solutions of metal halides:
Tony Cliff (born Yigael Glückstein, Hebrew: יגאל גליקשטיין; 20 May 1917 – 9 April 2000); Trotskyist anti-Zionist; prolific author of over twenty books, scholarly monographs and papers, pamphleteer and radical leftist activist, born in Ottoman Palestine; moved to Britain in 1947; assumed pen name 'Tony Cliff'; founding member and leader of Socialist Review Group, which became the International Socialists and then the Socialist Workers Party. Chapman Cohen writer on secularism Jackie Collins OBE (4 October 1937 – 19 September 2015) was an English romance novelist and actress. She wrote 32 novels, all of which appeared on The New York Times Best Seller list. Alan Coren (27 June 1938 – 18 October 2007) was an English humourist, writer and satirist who was a regular panellist on the BBC radio quiz The News Quiz and a team captain on BBC television's Call My Bluff. Coren, the author of over twenty books, was also a journalist, and for almost a decade was the editor of Punch magazine. His children, Giles and Victoria, are also writers Edwina Currie (née Cohen; born 13 October 1946) writer of six novels, broadcaster and former politician and media personality; from 1998 to 2003, hosted late evening talk show on BBC Radio 5 Live, Late Night Currie; moved to HTV, presenting Currie Night; has appeared in string of reality television programmes.
==== Study techniques ==== Much of what is known about cellular morphology changes and the effects of Rho proteins comes from the creation of a constitutively active mutated form of the protein. Mutation of a key amino acid can alter the conformation of the entire protein, causing it to permanently adopt a conformation that resembles the GTP-bound state. This protein cannot be inactivated normally, through GTP hydrolysis, and is thus "stuck on". When a Rho protein activated in this manner is expressed in 3T3 cells, morphological changes such as contractions and filopodia formation ensue. Because Rho proteins are G-proteins and plasma membrane bound, their location can be easily controlled. In each situation, whether it be wound healing, cytokinesis, or budding, the location of the Rho activation can be imaged and identified. For example, if a circular hole is inflicted in a spherical cell, Cdc42 and other active Rhos are seen in highest concentration around the circumference of the circular injury. One method of maintaining the spatial zones of activation is through anchoring to the actin cytoskeleton, keeping the membrane-bound protein from diffusing away from the region where it is most needed. Another method of maintenance is through the formation of a large complex that is resistant to diffusion and more rigidly bound to the membrane than the Rho itself.
== Plasticity == Cell plasticity is the idea that cells can switch phenotypes in response to environmental cues. In the context of regeneration, this environmental cue is damage or injury to a limb. Cell plasticity is closely related to dedifferentiation, implying that a cell with ‘plasticity’ can dedifferentiate to change phenotypes. Cell plasticity suggests that cells can change phenotypes slightly; not fully de-differentiating, to serve a better function. A strong example of this is lens regeneration in the newt.
Sources: en.wikipedia.org
23 September – Media outlets, including BBC News, report that a number of firearms officers have stepped back from their role within the Metropolitan Police after a colleague was charged with murder over the shooting of Chris Kaba. Former prime minister Boris Johnson warns present prime minister Rishi Sunak against building what he describes as a "mutilated" version of HS2 following reports that the northern leg of the route from Birmingham to Manchester could be scrapped amid concerns over spiralling costs. 24 September – The Ministry of Defence is offering the Metropolitan Police armed soldiers to support its officers after several firearms officers handed in their weapons. Greater Manchester becomes the first area of England to reverse bus deregulation with the launch of its Bee Network, whereby bus services are franchised by the local authority to bus companies. 25 September – NHS England announces that more than one million appointments and treatments have been lost due to strike action by NHS staff. Mayor of Greater Manchester Andy Burnham says that scrapping the HS2 rail link between Birmingham and Manchester risks "ripping the heart" out of plans to improve rail services across northern England. 27 September – Comer Homes Group is ordered to demolish two tower blocks it built as part of the Mast Quay Phase II complex after Greenwich Borough Council planners determined the blocks differed significantly from the original plans that were submitted and approved in 2012.
Robertson had been rejected as a candidate for the chair in physiology at Johns Hopkins University because his reputation had been "tarnished" not only by his decision to patent tethelin, but also by his association with its potential commercial exploitation. Robertson also learned that his long post-graduate association with American universities — rather than the (preferred at the time) post-graduate work in United Kingdom — had caused his application to join the newly founded Walter and Eliza Hall Institute of Research in Pathology and Medicine, as its first Director, to be rejected in favour of the successful candidate, Sydney W. Patterson M.B. B.S., M.D., D.Sc., who had studied in the UK at University College London, and had gained his Doctor of Science (D.Sc.) from the University of London. With a desire to return to Australia — and hoping to apply his acquired academic, administrative, and research skills, talents, and expertise to Australian circumstances — he accepted (in June 1919) the University of Adelaide's (April 1919) offer of a Chair, vacant since the (20 March 1919) death of Robertson's father-in-law, Sir Edward Stirling, who had been the university's Professor of Physiology; and, where, in the interim, Charles Kellaway, M.B. B.S., M.D., M.S. of Melbourne, had served as locum.
==== Neurocognitive consequences ==== Similarly to children, OSA affects cognitive functions in adults. Meta-analysis have shown that the most common cognitive impairments happen in the domains of attention, verbal and visual delayed long-term memory, visuospatial/constructional abilities and executive functions, such as mental flexibility. The executive functioning – mainly dominated by the prefrontal cortex – being significantly impaired in patients with OSA, it is believed that the prefrontal region and its connectivity are affected by sleep disorders. Regarding memory deficits, verbal memory is significantly impaired as patients struggle with immediate and delayed verbal information recall. While meta-analyses have shown no deficits in information retention for patients with OSA, those impairments in verbal memory may be linked to problems in encoding information. This deficit in encoding of information is also noticed in visuo-spatial memory; however, the visual memory seems to be intact in OSA patients. The cognitive impairments have been suggested to result from sleep fragmentation and sleep deprivation, as well as the excessive daytime sleepiness associated with them. More precisely, attention and memory deficits seem to result from sleep fragmentation, while deficits in global cognitive function (executive function, psychomotor function, language abilities) are more related to hypoxia or hypercarbia, which accompanies the obstructive events during sleep.
== Medical uses == Nandrolone esters are used clinically, although increasingly rarely, for people in catabolic states with major burns, cancer, and AIDS, and an ophthalmological formulation was available to support cornea healing. The positive effects of nandrolone esters include muscle growth, appetite stimulation and increased red blood cell production, and bone density. Clinical studies have shown them to be effective in treating anemia, osteoporosis, and breast cancer. Nandrolone sulfate has been used in an eye drop formulation as an ophthalmic medication.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.