The short version of Pro-Gly-Pro fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-23 and is reviewed periodically as new material appears.
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.
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.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
| 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 |
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.
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.
Hydraulic cement render (stucco) for finishing brick buildings in wet climates Hydraulic mortars for masonry construction of harbor works, etc., in contact with sea water Development of strong concretes Modern cements are often Portland cement or Portland cement blends, but other cement blends are used in some industrial settings.
== Indications == Based on guidelines published by the American Society of Colon and Rectal Surgery (ASCRS) in 2016, simple and complex anal fistulas were to be treated by fistulotomy or rubber band seton placement with fistulectomies being a secondary option. Fistulectomy can be considered in non-anorectal fistulas as well. In these circumstances, a fistulectomy may be the best option for the removal of a patient's diseased soft tissue.
Berry steps down from the post in order to run as Green candidate in Brighton Pavilion, where current MP Caroline Lucas is standing down at the next election. 8 May – John Swinney is sworn in as Scotland's seventh first minister at a ceremony at the Court of Session in Edinburgh. Swinney appoints Kate Forbes as Scotland's Deputy First Minister. The Conservative Member of Parliament for Dover Natalie Elphicke defects to the Labour Party. The Labour whip is restored to Kate Osamor. Former England cricketer Monty Panesar quits the Workers Party of Britain a week after being unveiled as one of its general election candidates. MSs vote 43–16 to approve the Senedd Reform Bill that will see the number of members increase from 60 to 96 at the next election. 9 May – Former cabinet minister Nadhim Zahawi says he will stand down from Parliament at the next election. Natalie Elphicke apologises for past comments in support of her ex-husband, Charlie, which she made when he was convicted of sexual assault. Swinney confirms to the BBC that the SNP's strategy of using the next general election as a mandate for a second referendum on Scottish independence remains. The government announces that a ban on sex offenders in England and Wales changing their name to avoid detection will be brought in. 10 May – The Scottish Government reaffirms its wish to see the Gender Recognition Reform (Scotland) Bill enacted.
Sources: en.wikipedia.org
Among the 18 known isotopes of einsteinium with mass numbers from 240 to 257, the most affordable is 253Es. It is an α-emitter with a half-life of 20.47 days, a relatively weak γ-emission and small spontaneous fission rate as compared with the isotopes of californium. Prolonged neutron irradiation also produces a long-lived isotope 254Es (t1/2 = 275.5 days). Twenty isotopes of fermium are known with mass numbers of 241–260. 254Fm, 255Fm and 256Fm are α-emitters with a short half-life (hours), which can be isolated in significant amounts. 257Fm (t1/2 = 100 days) can accumulate upon prolonged and strong irradiation. All these isotopes are characterized by high rates of spontaneous fission. Among the 17 known isotopes of mendelevium (mass numbers from 244 to 260), the most studied is 256Md, which mainly decays through electron capture (α-radiation is ≈10%) with a half-life of 77 minutes. Another alpha emitter, 258Md, has a half-life of 53 days. Both these isotopes are produced from rare einsteinium (253Es and 255Es respectively), that therefore limits their availability. Long-lived isotopes of nobelium and isotopes of lawrencium (and of heavier elements) have relatively short half-lives. For nobelium, 13 isotopes are known, with mass numbers 249–260 and 262. The chemical properties of nobelium and lawrencium were studied with 255No (t1/2 = 3 min) and 256Lr (t1/2 = 35 s). The longest-lived nobelium isotope, 259No, has a half-life of approximately 1 hour. Lawrencium has 14 known isotopes with mass numbers 251–262, 264, and 266.
=== Oxidation === The oxidation of isatin using hydrogen peroxide (Baeyer–Villiger oxidation) or chromic anhydride yields isatoic anhydride, a compound widely used either in herbicide products and in medicinal chemistry. The use of peroxydisulfuric acid gives rise to 1,4‑benzoxazine compounds.
In symbolic terms, he was seen as signifying parliamentary control over the Army. Issues of strategic policy during wartime were managed by the Northern and Southern Departments (the predecessors of today's Foreign Office and Home Office). From 1704 to 1855 the post of Secretary remained occupied by a minister of the second rank (although he was occasionally part of the Cabinet after 1794). Many of his responsibilities were transferred to the Secretary of State for War after the creation of that more senior post in 1794 (though the latter was also responsible for Britain's colonies from 1801, and renamed Secretary of State for War and the Colonies, an arrangement which only ceased with the establishment of the Colonial Office in 1854). From 1824 the British Empire (excepting India, which was administered separately by the East India Company and then the India Office) was divided by the War and Colonial Office into the following administrative departments: North America
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In its most discriminating form, genetic fingerprinting can uniquely discriminate any one person from the entire population of the world. Minute samples of DNA can be isolated from a crime scene and compared to that from suspects or from a DNA database of earlier evidence or convicts. Simpler versions of these tests are often used to rapidly rule out suspects during a criminal investigation. Evidence from decades-old crimes can be tested, confirming or exonerating the people originally convicted. Forensic DNA typing has been an effective way of identifying or exonerating criminal suspects due to analysis of evidence discovered at a crime scene. The human genome has many repetitive regions that can be found within gene sequences or in non-coding regions of the genome. Specifically, up to 40% of human DNA is repetitive. There are two distinct categories for these repetitive, non-coding regions in the genome. The first category is called variable number tandem repeats (VNTR), which are 10–100 base pairs long, and the second category is called short tandem repeats (STR), and these consist of repeated 2–10 base pair sections. PCR is used to amplify several well-known VNTRs and STRs using primers that flank each of the repetitive regions. The sizes of the fragments obtained from any individual for each of the STRs will indicate which alleles are present. By analyzing several STRs for an individual, a set of alleles for each person will be found that statistically is likely to be unique. Researchers have identified the complete sequence of the human genome.
=== Food safety === Water activity is used in many cases as a critical control point for Hazard Analysis and Critical Control Points (HACCP) programs. Samples of the food product are periodically taken from the production area and tested to ensure water activity values are within a specified range for food quality and safety. Measurements can be made in as little as five minutes, and are made regularly in most major food production facilities. For many years, researchers tried to equate bacterial growth potential with water content. They found that the values were not universal, but specific to each food product. W. J. Scott first established that bacterial growth correlated with water activity, not water content, in 1953. It is firmly established that growth of bacteria is inhibited at specific water activity values. U.S. Food and Drug Administration (FDA) regulations for intermediate moisture foods are based on these values. Lowering the water activity of a food product should not be seen as a kill step. Studies in powdered milk show that viable cells can exist at much lower water activity values, but that they never grow. Over time, bacterial levels decline.
In January 2022, distribution of Lilly's COVID-19 antibody drug was paused due to lack of efficacy against the emerging omicron variant. A second COVID-19 monoclonal antibody therapy, bebtelovimab, developed with AbCellera, was granted Emergency Use Authorization in February 2022, with the U.S. government committing to a $720 million purchase of up to 600,000 doses. In May 2022, the FDA approved Lilly's type 2 diabetes drug Mounjaro (tirzepatide). In August 2022, following the overturning of Roe v. Wade in the Dobbs decision, the state of Indiana passed a near total ban on abortion, and Lilly said the move would make it difficult to attract talent to the state and that it would be forced to look for "more employment growth" elsewhere. In October 2022, Lilly acquired the gene therapy developer Akouos for $487 million in upfront and $123 million deferred payments. In early 2020, Lilly introduced the Lilly Insulin Value Program, where people who have commercial insurance or no insurance can receive a savings card to fill their entire monthly prescription of any Lilly insulin for $35. In 2023, the Inflation Reduction Act extended a similar concept across all insulin suppliers by capping out-of-pocket costs for insulin at $35 per monthly prescription among Medicare Parts B and D enrollees. In January 2023, Lilly and TRexBio announced a collaboration and license agreement for three assets to treat immune-mediated diseases. TRexBio received an upfront payment of $55 million as part of this deal.
The American tea culture is a part of the history of the United States, as tea has appealed to all classes and has adapted to the customs of the United States. The Native peoples of North America drank various herbal teas, the most common of which was Yaupon tea, known as the "Beloved drink", "Cassina", or "White drink". It was brewed from yaupon holly (Ilex vomitoria), which is native to the Atlantic and Gulf Coasts. Native American tribes like the Chickasaw, Cherokee, Choctaw, Muscogee, and Timucua used the tea as a daily drink, as a social drink used in meetings, and in various rituals, many of which were associated with purification. Yaupon tea was adopted by European colonists as early as the 17th century who gave it various names like "Black drink", "Carolina Tea", "South Seas Tea", or "Indian tea".
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 modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.