heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-26 and is reviewed periodically as new material appears.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
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.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
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.
All chemical elements derive from stellar nucleosynthesis except for hydrogen and some helium and lithium. Basic chemical ingredients of life – the carbon–hydrogen molecule (CH), the carbon–hydrogen positive ion (CH+) and the carbon ion (C+) – can be produced by ultraviolet light from stars. Complex molecules, including organic molecules, form naturally both in space and on planets. Organic molecules on the early Earth could have had either terrestrial origins, with organic molecule synthesis driven by impact shocks or by other energy sources, such as ultraviolet light, redox coupling, or electrical discharges; or extraterrestrial origins (pseudo-panspermia), with organic molecules formed in interstellar dust clouds or in the solar nebula accumulating onto the planet.
{\displaystyle {\begin{cases}{\ce {^{244}_{96}Cm ->[{\ce {(\alpha,n)}}] ^{247}_{98}Cf ->[\epsilon][3.11 \ {\ce {h}}] ^{247}_{97}Bk}}\\{\ce {^{244}_{96}Cm ->[{\ce {(\alpha,p)}}] ^{247}_{97}Bk}}\end{cases}}}
Tecemotide (INN; emepepimut-S (USAN); formerly known as BLP25 or EMD 531444) is a synthetic lipopeptide that is used as antigen in an investigational therapeutic cancer vaccine (formerly known as Stimuvax, L-BLP25, BLP25 liposomal vaccine, or BLP25 liposome vaccine). The investigational therapeutic cancer vaccine is designed to induce a cellular immune response to cancer cells that express MUC1, a glycoprotein antigen that is widely over-expressed on common cancers such as lung cancer, breast cancer, prostate cancer, and colorectal cancer. The cellular immune response may lead to a rejection of tumor tissue expressing the MUC1 antigen.
The conservation and restoration of waterlogged wood is the process undertaken by conservator-restorers of caring for and maintaining waterlogged wooden artefacts to preserve their form, and the information they contain. It covers the processes that can be taken by conservators, archaeologists, and other museum professionals to conserve waterlogged wood. This practice includes understanding the composition and agents of deterioration of waterlogged wood, as well as the preventive conservation and interventive conservation measures that can be taken.
=== Alpha cell dysfunction === Onset of autoimmune diabetes is accompanied by impaired ability to regulate the hormone glucagon, which acts in antagonism with insulin to regulate blood sugar and metabolism. Progressive beta cell destruction leads to dysfunction in the neighboring alpha cells, which secrete glucagon, exacerbating excursions away from euglycemia in both directions; overproduction of glucagon after meals causes sharper hyperglycemia, and failure to stimulate glucagon upon hypoglycemia prevents a glucagon-mediated rescue of glucose levels.
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Estradiol (E2), also called oestrogen, oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of female reproductive cycles such as estrous and menstrual cycles. Estradiol is responsible for the development of female secondary sexual characteristics such as the breasts, widening of the hips and a female pattern of fat distribution. It is also important in the development and maintenance of female reproductive tissues such as the mammary glands, uterus and vagina during puberty, adulthood and pregnancy. It also has important effects in many other tissues including bone, fat, skin, liver, and the brain. Though estradiol levels in males are much lower than in females, estradiol has important roles in males as well. Apart from humans and other mammals, estradiol is also found in most vertebrates and crustaceans, insects, fish, and other animal species. Estradiol is produced within the follicles of the ovaries and in other tissues including the testicles, the adrenal glands, fat, liver, the breasts, and the brain. Estradiol is produced in the body from cholesterol through a series of reactions and intermediates. The major pathway involves the formation of androstenedione, which is then converted by aromatase into estrone and is subsequently converted into estradiol. Alternatively, androstenedione can be converted into testosterone, which can then be converted into estradiol. Upon menopause in females, production of estrogens by the ovaries stops and estradiol levels decrease to very low levels.
== External links == 'When Heroin Was Legal' BBC Drug-poisoning Deaths Involving Heroin: United States, 2000–2013 US Department of Health and Human Services Heroin Trafficking in the United States Archived 18 July 2020 at the Wayback Machine (2019) US Congressional Research Service
It has been suggested that the three fundamental factors underlying chronic wound pathogenesis are cellular and systemic changes of aging, repeated bouts of ischemia-reperfusion injury, and bacterial colonization with resulting inflammatory host response.
CD38 (cluster of differentiation 38), also known as cyclic ADP ribose hydrolase, is a glycoprotein found on the surface of many immune cells (white blood cells), including CD4+, CD8+, B lymphocytes and natural killer cells. CD38 also functions in cell adhesion, signal transduction and calcium signaling. In humans, the CD38 protein is encoded by the CD38 gene which is located on chromosome 4. CD38 is a paralog of CD157, which is also located on chromosome 4 (4p15) in humans.
== History == Since its discovery in 1967, serine protease DPP-4 has been a popular subject of research. Inhibitors of DPP-4 have long been sought as tools to elucidate the functional significance of the enzyme. The first inhibitors were characterized in the late 1980s and 1990s. Each inhibitor was important to establish an early structure activity relationship (SAR) for subsequent investigation. The inhibitors fall into two main classes, those that interact covalently with DPP-4 and those that do not. DPP-4 is a dipeptidase that selectively binds substrates that contain proline at the P1-position, thus many DPP-4 inhibitors have 5-membered heterocyclic rings that mimic proline, e.g. pyrrolidine, cyanopyrrolidine, thiazolidine and cyanothiazolidine. These compounds commonly form covalent bonds to the catalytic residue Ser630. In 1994, researchers from Zeria Pharmaceuticals unveiled cyanopyrrolidines with a nitrile function group that was assumed to form an imidate with the catalytic serine. Concurrently other DPP-4 inhibitors without a nitrile group were published but they contained other serine-interacting motifs, e.g. boronic acids, phosphonates or diacyl hydroxylamines. These compounds were not as potent because of the similarity of DPP-4 and prolyl oligopeptidase (PEP) and also suffered from chemical instability. Ferring Pharmaceuticals filed for patent on two cyanopyrrolidine DPP-4 inhibitors, which they published in 1995. These compounds had excellent potency and improved chemical stability. In 1995, Edwin B.
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In Indian media, Morea has often been referred to as a "Chocolate Boy", a term used to describe his youthful appearance and conventional attractiveness. He dominated and redefined the Indian modeling scene before male modeling was mainstream, gained international recognition, had the perfect look for print and runway, and bridged the gap to Bollywood, influencing generations after him. He has been noted for his commitment to his roles and described as having a versatile screen presence. A 2008 feature in India Today titled "The Boylet Club" identified him as one of Bollywood's "alpha males" of the time. South China Morning Post cited him as one of the top Indian male models who successfully transitioned into acting. In 2025, The Times of India marked him “…the unforgettable 90s heroes who became India’s first big crushes”, describing him as “tall, white, and incredibly handsome”. Motherland magazine regarded him as 'Supermodel of 2000s'. Film critics and journalists have occasionally commented on his style and performances; Onkar Kulkarni of Times of India referred to him as a "stylish superhero," while Taran Adarsh of Bollywood Hungama remarked on his sincerity and screen presence. In February 1999, Morea appeared on the cover of the international edition of Elle magazine. He clinched 13th place on "India's most handsome man" by WebIndia123. He ranked on The Times of India's "50 Most Desirable Men" list for multiple years, including 13th in 2009, and between 30th and 45th place from 2010 to 2014.
Passing alpha particles through a very thin glass window and trapping them in a discharge tube allowed researchers to study the emission spectrum of the captured particles, and ultimately proved that alpha particles are helium nuclei. Other experiments showed beta radiation, resulting from decay and cathode rays, were high-speed electrons. Likewise, gamma radiation and X-rays were found to be high-energy electromagnetic radiation. The relationship between the types of decays also began to be examined: For example, gamma decay was almost always found to be associated with other types of decay, and occurred at about the same time, or afterwards. Gamma decay as a separate phenomenon, with its own half-life (now termed isomeric transition), was found in natural radioactivity to be a result of the gamma decay of excited metastable nuclear isomers, which were in turn created from other types of decay. Although alpha, beta, and gamma radiations were most commonly found, other types of emission were eventually discovered. Shortly after the discovery of the positron in cosmic ray products, it was realized that the same process that operates in classical beta decay can also produce positrons (positron emission), along with neutrinos (classical beta decay produces antineutrinos).
Eye exposure: 18 mg (0.28 gr)/6 hours (rabbit) Oral: 72 mg/kg (0.00115 oz/lb) (rat, LD50), 1,186 mg/kg (0.01898 oz/lb) (rat, TDLo), 5,112 mg/kg (0.08179 oz/lb) (rat, TD) Inhalation: 12,500 ppm (human, TCLo), 960 ppm/4 hours (dog, LC50) 33–50 ppm (rat or mouse, TC), 800 ppm/4 hours (rat or mouse, LC50) Subcutaneous injection: 100 mg/kg (0.0016 oz/lb) (cat, LDLo), 292 mg/kg (0.00467 oz/lb) (mouse, TDLo) 900–2,600 mg/kg (0.014–0.042 oz/lb) (mouse, TD), 187 mg/kg (0.00299 oz/lb) (rat, LD50). Intraperitoneal injection: 750 mg/kg (0.0120 oz/lb) (mouse, TDLo), 175 mg/kg (0.00280 oz/lb) (mouse, LD50) Intravenous injection: 175 mg/kg (0.00280 oz/lb) (rabbit, LD50), 290 mg/kg (0.0046 oz/lb) (mouse, LD50) The US Environmental Protection Agency (USEPA) estimated in 2016 that for low doses, the inhalation of ethylene oxide for a lifetime could increase an individual's lifetime cancer risk by as much as 3.0 × 10−3 per μg/m3 (without considering that early-life exposures are likely more potent). The USEPA estimated the slope of the dose-response declines at higher doses, and extra cancer risk estimates for several occupational exposure scenarios are calculated.
== Journalists == David Aaronovitch, English journalist, television presenter and author. He is the author of Paddling to Jerusalem: An Aquatic Tour of Our Small Country (2000), Voodoo Histories: the role of Conspiracy Theory in Modern History (2009) and Party Animals: My Family and Other Communists (2016). He won the Orwell Prize for political journalism in 2001, and the What the Papers Say "Columnist of the Year" award in 2003. He previously wrote for The Independent, The Guardian and The Times. Barbara Amiel; a British-Canadian conservative journalist, writer, and socialite. Ian Austin, Baron Austin of Dudley (born 6 March 1965), journalist for The Daily Mail, the Daily Telegraph, The Guardian and Jewish Chronicle; life peer in House of Lords; was Member of Parliament (MP); was political advisor to Chancellor of the Exchequer (later Prime Minister), Gordon Brown; was Assistant Whip for the Government; was member of Labour Friends of Israel. Antony Barnett investigative journalist; has worked as a reporter and presenter for Channel 4's Dispatches, The Observer where he held a number of posts including as the newspaper's Investigations Editor; Barnett's undercover investigation "The Battle for the Labour Party" won British Journalism Award for political journalism; co-founder of openDemocracy and has written for Jewish Chronicle, The Guardian HuffPost UK, New York Review of Books, Common Dreams, New Statesman, The Lancet, Prospect Magazine, The Bureau of Investigative Journalism, LabourList, Eurozine, Byline Times.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
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.