A practical reference on heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-18 and is reviewed periodically as new material appears.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
The K-pop and K-drama industries are generally saturated with fair-skinned celebrities, some of whom serve as brand ambassadors and beauty ideals. The increasing popularity of South Korean culture and K-beauty has been a factor in popularizing the skin whitening trend elsewhere in Asia, especially in poorer countries like Thailand, where many have begun to use unsafe skin-whitening products. In Nepal, cultural influence from Bollywood, which prominently features lighter skinned lead actors, has been linked to the use of skin whitening creams among some darker-skinned men. Other motivations for skin whitening include desiring softer skin and wanting to conceal discolorations arising from pimples, rashes, or chronic skin conditions. Individuals with depigmenting conditions such as vitiligo have also been known to lighten their skin to achieve an even skin tone.
That analysis was based on Israeli women with breast implants as confirmed by medical records, and the analyses of diseases were based on diagnoses made after the women got breast implants that were included in medical records during up to 20 years of follow-up. A published study of U.S. women with similar results was published in 2019 by Coroneos and his colleagues at MD Anderson Medical Center. The data were based on two studies with a combined total of almost 100,000 women with breast implants, but many dropped out of the study within a few years of their breast implant surgery. However, of the women in the study for at least two years, the researchers reported an 800% increase in Sjögren syndrome, 700% increase in scleroderma, and almost 600% increase in rheumatoid arthritis among women with breast implants compared to the general population of women of the same age and demographics. Recent research on women who reported autoimmune and other system symptoms but were not diagnosed with an autoimmune disease evaluated whether the women's symptoms changed after their implants were removed. A 2020 study on the effectiveness of explant surgery on women with breast implant illness found that nearly all of 750 women who underwent explant surgery reported a significant improvement in their health within a month after their surgery.
The Treuhandanstalt (German: [ˈtʁɔɪ̯hantˌʔanʃtalt] , "Trust agency"), colloquially referred to as Treuhand, was a government agency of the German Democratic Republic (East Germany) from June to October 1990 and reunified Germany from 1990 to 1994, responsible for the reprivatisation/privatisation of the Volkseigene Betriebe (VEBs) and other state-owned enterprises in East Germany. The Treuhand was established by the Volkskammer of East Germany during Die Wende, to oversee the restructure and sale of about 8,500 state-owned companies with over four million employees – the world's largest industrial enterprise, controlling everything from steel works to the Babelsberg Studios. It inherited the assets of the Socialist Unity Party of Germany and other East German government agencies after German reunification in October 1990. The Treuhand was dissolved by the Federal Government of Germany on 1 January 1995 and reconstituted as the Federal Agency for Special Tasks Related to Unification (Bundesanstalt für vereinigungsbedingte Sonderaufgaben) which was active until 2000. The Treuhand has faced criticism and opposition for its handling of the privatisation process in the former East Germany, particularly for excessive liquidation and the resulting layoffs. On 1 April 1991, Treuhand chairman Detlev Karsten Rohwedder was assassinated by the Red Army Faction (RAF), a West German far-left terrorist group sponsored and supported by the East German Stasi. The shooter has never been identified.
Sources: en.wikipedia.org
Many described the separation from family members as excruciating, with some children being unable to talk to their parents, living with relatives in Gaza or having to monitor and parent younger siblings while their parents care for their injured siblings. On 16 August 2025, the U.S. State Department announced that it had suspended the issuance of visitor visas to people from the Gaza Strip, including children who require urgent medical care. In January–April 2024, medical evacuations for children from Gaza averaged about 296 per month; by late 2024 the rate had fallen to under one per day. In October 2024, UNICEF said children were dying not only from the violence itself but also because survivors were often unable to leave Gaza for urgent, life-saving treatment. By July/September 2025, an estimated 2,500-4,500 of critically wounded children are waiting for permits to be evacuated for care.
== Cut anatomy and structure == The sirloin steak has several muscles that define the texture and flavor of different cuts. The sirloin does not do much work in supporting the cow, and so does not contain much reinforcing connective tissue. This makes the sirloin tender. The top sirloin primarily contains the Gluteus medius, along with the gluteus accessorius, gluteus profundus, and part of the biceps femoris. During butchery, these parts are separated along natural seams. These muscles differ in size and function. The gluteus medius is the largest and most prominent portion of the steak. These muscles contain connective tissue that contributes to differing tenderness between cuts. The gluteus medius cut is consistently tender. Heavily worked muscles, like the biceps femoris, are often firmer and more flavorful. The top sirloin cooks quicker than the bottom sirloin and is good for pan-searing and grilling. The bottom sirloin contains more muscles and is typically roasted or braised.
Like most brainstem tumors, diagnosing diffuse intrinsic pontine glioma usually involves non-invasive brain imaging like MRI, in addition to neurologic physical exam. Biopsies and other surgical procedures are also used when possible. Similar to DIPG, diffuse midline gliomas (DMG) often fall into similar categories for both diagnosis and treatment as DIPG and are often categorized together. More recently, biopsies are performed so that the best option for clinical trials can be chosen. In studies resulting from the DIPG/DMG Registry and in connection with the DIPG/DMG Collaborative, statistics reveal that approximately 150–300 patients are diagnosed with DIPG in the USA per year, the median age of patients with DIPG is approximately 6–7 years old, and the male/female ratio of DIPG patients is 1:1.
Sources: en.wikipedia.org
Observation of the development of living organisms shows that they are characterized by the tendency to store a maximum amount of information, both about the environment and about themselves. This information then leads to an abstract analysis, which plays an important role in the development of life forms. Thus, Kardashev defines civilization from a functional perspective as "a state of very stable matter capable of acquiring, abstractly analyzing and applying information in order to extract data about the environment and itself, in order to develop survival reactions ". However, this functional definition of civilization implies that it cannot have a goal or end, since it is based on the principle of accumulating more and more information. Taking up von Hoerner's categories, Kardashev sees four possible scenarios for the development of civilizations:
== Ecology == Yeasts are very common in the environment, and are often isolated from sugar-rich materials. Examples include naturally occurring yeasts on the skins of fruits and berries (such as grapes, apples, or peaches), and exudates from plants (such as plant saps or cacti). Some yeasts are found in association with soil and insects. Yeasts from the soil and from the skins of fruits and berries have been shown to dominate fungal succession during fruit decay. The ecological function and biodiversity of yeasts are relatively unknown compared to those of other microorganisms. Yeasts, including Candida albicans, Rhodotorula rubra, Torulopsis and Trichosporon cutaneum, have been found living in between people's toes as part of their skin flora. Yeasts are also present in the gut flora of mammals and some insects and even deep-sea environments host an array of yeasts. An Indian study of seven bee species and nine plant species found 45 species from 16 genera colonize the nectaries of flowers and honey stomachs of bees. Most were members of the genus Candida; the most common species in honey stomachs was Dekkera intermedia and in flower nectaries, Candida blankii. Yeast colonising nectaries of the stinking hellebore have been found to raise the temperature of the flower, which may aid in attracting pollinators by increasing the evaporation of volatile organic compounds. A black yeast has been recorded as a partner in a complex relationship between ants, their mutualistic fungus, a fungal parasite of the fungus and a bacterium that kills the parasite.
In one of Song Ci's accounts (Washing Away of Wrongs), the case of a person murdered with a sickle was solved by an investigator who instructed each suspect to bring his sickle to one location. (He realized it was a sickle by testing various blades on an animal carcass and comparing the wounds.) Flies, attracted by the smell of blood, eventually gathered on a single sickle. In light of this, the owner of that sickle confessed to the murder. The book also described how to distinguish between a drowning (water in the lungs) and strangulation (broken neck cartilage), and described evidence from examining corpses to determine if a death was caused by murder, suicide or accident. Methods from around the world involved saliva and examination of the mouth and tongue to determine innocence or guilt, as a precursor to the Polygraph test. In ancient India, some suspects were made to fill their mouths with dried rice and spit it back out. Similarly, in ancient China, those accused of a crime would have rice powder placed in their mouths. In ancient middle-eastern cultures, the accused were made to lick hot metal rods briefly. It is thought that these tests had some validity since a guilty person would produce less saliva and thus have a drier mouth; the accused would be considered guilty if rice was sticking to their mouths in abundance or if their tongues were severely burned due to lack of shielding from saliva.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.