Heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-07-20. Anything still debated is marked as such rather than presented as settled.
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.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
| 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 |
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
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.
Fossil fuel use and production, e.g. incompletely combusted fossil fuels or unintended evaporation of fuels. The most prevalent VOC is ethane, a relatively inert compound. Solvents used in coatings, paints, and inks. Approximately 12 billion litres of paint are produced annually. Typical solvents include aliphatic hydrocarbons, ethyl acetate, glycol ethers and acetone. Motivated by cost, environmental concerns, and regulation, the paint and coating industries are increasingly shifting toward aqueous solvents. Compressed aerosol products, mainly butane and propane, estimated to contribute 1.3 million tonnes of VOC emissions per year globally. Biofuel use, e.g., cooking oils in Asia and bioethanol in Brazil. Biomass combustion, especially from rain forests. Although combustion principally releases carbon dioxide and water, incomplete combustion affords a variety of VOCs.
=== Orthogonal sets in model organisms === The orthogonal pairs of synthetase and tRNA that work for one organism may not work for another, as the synthetase may mis-aminoacylate endogenous tRNAs or the tRNA be mis-aminoacylated itself by an endogenous synthetase. As a result, the sets created to date differ between organisms.
These conditions are valid in a general way. The mathematical formulation of the gap depends upon the kinematics of the underlying theory of the solid (e.g., linear or nonlinear solid in two- or three dimensions, beam or shell model). By restating the normal stress
=== In-orbit activities === At the start of the third orbit, Cooper checked his list of 11 experiments that were on his schedule. His first task was to eject a six-inch (152 mm) diameter sphere, equipped with xenon strobe lights, from the nose of the spacecraft. This experiment was designed to test his ability to spot and track a flashing beacon in orbit. At T+3 hours 25 minutes, Cooper flipped the switch and heard and felt the beacon detach from the spacecraft. He tried to see the flashing light in the approaching dusk and on the nightside pass, but failed to do so. On the fourth orbit, he did spot the beacon and saw it pulsing. Cooper reported to Scott Carpenter on Kauai, Hawaii, "I was with the little rascal all night." He also spotted the beacon on his fifth and sixth orbits. Also on the sixth orbit, at about T+9 hours, Cooper set up cameras, adjusted the spacecraft attitude and set switches to deploy a tethered balloon from the nose of the spacecraft. It was a 30-inch (762 mm) PET film balloon painted fluorescent orange, inflated with nitrogen and attached to a 100-foot (30 m) nylon line from the antenna canister. A strain gauge in the antenna canister would measure differences in atmospheric drag between the 100-mile (160 km) perigee and the 160-mile (260 km) apogee. Cooper tried several times to eject the balloon, but it failed to eject. Cooper passed Schirra's orbital record on the seventh orbit while he was engaged in radiation experiments. After 10 hours, the Zanzibar tracking station informed Cooper the flight was a go for 17 orbits.
== History == 4-HO-MET was first synthesized and discovered by Alexander Shulgin in the 1970s. It was first described in the scientific literature by David Repke and colleagues by 1981. Subsequently, 4-HO-MET was described by Shulgin in his book TiHKAL (Tryptamines I Have Known and Loved) in 1997 as being- aside from its synthesis- indistinguishable from any other ethyl homologue. It was encountered as a novel recreational and designer drug in Europe by 2008 and recently in the United States in 2025.
Sources: en.wikipedia.org
During an interview for Al Jazeera television on 17 November 2005, he said his election as MP earlier in the year was "despite all the efforts made by the British government, the Zionist movement and the newspapers and news media which are controlled by Zionism". In Trials of the Diaspora: A History of Anti-Semitism in England, Anthony Julius cites this interview as one example of Galloway pandering to the antisemitic prejudices of his audience. According to Julius, Galloway merely refers to the "right-wing press" in the British media, whereas he has the habit of adding the word "Zionist" when speaking on television in the Arab world. A few years later, in a May 2009 speech given at a meeting in Westminster, Galloway said: "I do not agree with the argument that there is a shadowy Jewish influence. Israel is doing what America wants it to do and to argue otherwise is to go down the dark tunnel of racist antisemitism". Galloway criticised the British government's support of Israel during the Gaza war and condemned the genocide of Palestinians in the Gaza Strip. Galloway disputed reports from the Israeli government about the October 7 attacks. Specifically, he disputed the number of babies killed and suggested two-thirds of those killed were from the IDF. He also suggested that those who propagate the official Israeli government account of 7 October are "war criminals". The Board of Deputies of British Jews, the largest Jewish community organisation in the UK, has called Galloway "a demagogue and conspiracy theorist".
== Career == McAlpine returned to Canada after her PhD to work as a postdoctoral fellow at Queen's University from 1970 to 1972 in the group of Nancy Simpson. McAlpine participated in a project to study genetic traits of peoples in the Arctic, living in northern Canada for a month in 1970. In 1972, she started working at the University of Manitoba. Her main research focus was on mapping human genes. She served on the university senate between 1981 and 1985 and was Chair of the University Discipline Committee between 1990 and 1994. She was granted full professorship in 1985. From 1993 until her death, she was Chair of the Department of Human Genetics. McAlpine was part of a group of geneticists who recognised the importance of standardised nomenclatures across all human genes and homologous genes in other species. She founded the HUGO Gene Nomenclature Committee and was Chair of the committee from 1992 until 1996. When she retired, her workload was so significant as to be divided between three full-time staff members. She contributed to the creation of guidelines and provided pre-publication services to researchers to ensure consistent gene labelling. She became known as the foremost expert and leader in gene nomenclature. McAlpine was also a member of the American Society of Human Genetics since 1965 and was president of the Genetics Society of Canada in 1995. She was President of the Manitoba Chapter of the Canadian Association of Women in Science in 1993–1994.
== Television episodes == "Half-Life", Icons season 3, episode 17 (2004) "Half-Life", Odyssey 5 episode 17 (2002) "Half Life", La Femme Nikita season 2, episode 7 (1998) "Half Life", Logan's Run episode 6 (1977) "Half Life", Medical Investigation episode 17 (2005) "Half Life", New Tricks series 8, episode 9 (2011) "Half Life", Sea Patrol season 3, episode 7 (2009) "Half Life", SeaChange season 3, episode 13 (2000)
Steroid hormones are converted from their parent compound, cholesterol. Mammalian steroid hormones can be grouped into five groups by the receptors to which they bind: glucocorticoids, mineralocorticoids, androgens, estrogens, and progestogens. Some forms of vitamin D, such as calcitriol, are steroid-like and bind to homologous receptors, but lack the characteristic fused ring structure of true steroids.
A chipotle ( chih-PO(H)T-lay, Spanish: [tʃiˈpotle]), or chilpotle, is a smoke-dried ripe jalapeño chili pepper used for seasoning. It is used primarily in Mexican and Mexican-inspired cuisines, such as Tex-Mex and Southwestern United States dishes. It comes in different forms, such as chipotles en adobo (stewed in adobo sauce).
Sources: en.wikipedia.org
=== Reduced NMDA‐receptor function === Reduced NMDA receptor function has been linked to reduced social interactions, locomotor hyperactivity, self-injury, prepulse inhibition (PPI) deficits, and sensory hypersensitivity, among others. Results suggest that NMDA dysregulation could contribute to core ASD symptoms.
Secretary of Treasury Scott Bessent joined the trip after having met with Chinese vice premier He Lifeng in South Korea. Within the Trump family, Trump's son Eric and his wife Lara also joined the visit. On 12 April, a spokesperson for The Trump Organisation told Reuters, Eric and Lara Trump "will accompany Trump in a personal capacity on the May 12 to 15 visit." Reuters noted that this may represent a conflict of interest, given that "Trump's personal wealth and business dealings are managed by Eric and other members of his family." Unlike in 2017, Trump's wife Melania did not join the trip. On 8 May, news circulated that a delegation of American CEOs representing the business community would join Trump on his visit. The White House distributed a list of business executives who would visit with Trump on 11 May, including Elon Musk of Tesla and Tim Cook of Apple Inc. Nvidia CEO Jensen Huang, who had not initially been invited, boarded Air Force One in Alaska to accompany Trump to China. The final list of CEOs included:
=== Use by non-military groups === Terrorist groups have used C-4 worldwide in acts of terrorism and insurgency, as well as domestic terrorism and state terrorism. On May 13, 1985, the Philadelphia Police Department dropped a C-4 bomb on the home of the MOVE organization, killing eleven people — including five children — and wiping out 61 homes in two city blocks in a subsequent fire. Composition C-4 is recommended in al-Qaeda's traditional curriculum of explosives training. In October 2000, the group used C-4 to attack the USS Cole, killing 17 sailors. In 1996, Saudi Hezbollah terrorists used C-4 to blow up the Khobar Towers, a U.S. military housing complex in Saudi Arabia. Composition C-4 has also been used in improvised explosive devices by Iraqi insurgents.
== Chemistry == Prednisolone is a synthetic pregnane corticosteroid closely related to its cognate prednisone, having identical structure save for two fewer hydrogens near C11. It is also known as δ1-cortisol, δ1-hydrocortisone, 1,2-dehydrocortisol, or 1,2-dehydrohydrocortisone, as well as 11β,17α,21-trihydroxypregna-1,4-diene-3,20-dione.
22 December – Circuit Court judge Gerard O'Brien was convicted of the sexual assault of six young men when he was a secondary school teacher during the 1990s. O'Brien is also a former Fianna Fáil party councillor and former State solicitor. He was born with no arms and just one leg as a result of the drug thalidomide. 24 December A man in his 20s died and a second man was seriously injured in a gangland gun attack at a restaurant in Blanchardstown, Dublin. Two men appeared in court in Limerick in connection with a seizure of 300 kg of cocaine worth an estimated €21 million. 28 December – Met Éireann recorded the warmest year on record, with the overall average temperature for Ireland rising above 11 °C (51.8 °F) for the first time.
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.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.