The short version of TKPRPGP fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
| 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 |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
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.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
On March 23 2023, Brazilian police raided the Salgueiro favela in São Gonçalo, Rio de Janeiro, killing Leonardo Costa Araujo, the head of CV in Para, and other 12 gangsters. On September 4 2025, eight members of the Terceiro Comando Puro were killed in a shootout with police in Rio de Janeiro. Later, on October 28, 2025, against the backdrop of COP30, Brazilian police launched Operation Containment on Comando Vermelho spots in Rio de Janeiro, arresting at least 81 suspected gang members while resulting in the deaths of more than 132 people, including four police officers and at least 17 residents without prior criminal records. On 14 January 2026, four people were killed in a police operation against the Comando Vermelho in the Salgueiro favela of Rio de Janeiro. On 18 March, eight people, including Comando Vermelho commander Claudio Augusto dos Santos, were killed in police raids across Rio de Janeiro.
The successful incorporation of a third base pair is a significant breakthrough toward the goal of greatly expanding the number of amino acids which can be encoded by DNA, from the existing 20 amino acids to a theoretically possible 172, thereby expanding the potential for living organisms to produce novel proteins. Earlier, the artificial strings of DNA did not encode for anything, but scientists speculated they could be designed to manufacture new proteins which could have industrial or pharmaceutical uses. Transcription of DNA containing unnatural base pairs and translation of corresponding mRNA were actually achieved recently. In November 2017, the same team at the Scripps Research Institute that first introduced two extra nucleobases into bacterial DNA reported having constructed a semi-synthetic E. coli bacteria able to make proteins using such DNA. Its DNA contained six different nucleobases: four canonical and two artificially added, dNaM and dTPT3 (these two form a pair). The bacteria had two corresponding RNA bases included in two new codons, additional tRNAs recognizing these new codons (these tRNAs also contained two new RNA bases within their anticodons) and additional amino acids, enabling the bacteria to synthesize "unnatural" proteins. Another demonstration of UBPs were achieved by Ichiro Hirao's group at RIKEN institute in Japan.
CYP1A2 (strongly) which metabolizes agomelatine, amitriptyline, caffeine, clomipramine, clozapine, duloxetine, haloperidol, imipramine, phenacetin, tacrine, tamoxifen, theophylline, olanzapine, etc. CYP3A4 (moderately) which metabolizes alprazolam, aripiprazole, clozapine, haloperidol, quetiapine, pimozide, ziprasidone, etc. CYP2D6 (weakly) which metabolizes aripiprazole, chlorpromazine, clozapine, codeine, fluoxetine, haloperidol, olanzapine, oxycodone, paroxetine, perphenazine, pethidine, risperidone, sertraline, thioridazine, zuclopenthixol, etc. CYP2C9 (moderately) which metabolizes nonsteroidal anti-inflammatory drugs, phenytoin, sulfonylureas, etc. CYP2C19 (strongly) which metabolizes clonazepam, diazepam, phenytoin, etc. CYP2B6 (weakly) which metabolizes bupropion, cyclophosphamide, sertraline, tamoxifen, valproate, etc. By so doing, fluvoxamine can increase serum concentration of the substrates of these enzymes. Fluvoxamine may also elevate plasma levels of olanzapine by approximately two times. Combined olanzapine and fluvoxamine, which may cause increased sedation, should be used cautiously and controlled clinically and by therapeutic drug monitoring to avoid olanzapine induced adverse effects and/or intoxication. The plasma levels of oxidatively metabolized benzodiazepines (e.g., triazolam, midazolam, alprazolam, and diazepam) are likely to be increased when co-administered with fluvoxamine.
=== Eukaryotic mRNA turnover === Inside eukaryotic cells, there is a balance between the processes of translation and mRNA decay. Messages that are being actively translated are typically associated with cap-binding and translation initiation factors and with poly(A)-binding protein, which can antagonize deadenylation and decapping and help protect mRNA ends from decay machinery. The balance between translation and decay is reflected in the size and abundance of cytoplasmic structures known as P-bodies. The poly(A) tail of the mRNA is shortened by specialized exonucleases that are targeted to specific messenger RNAs by a combination of cis-regulatory sequences on the RNA and trans-acting RNA-binding proteins. Poly(A) tail removal is thought to disrupt the circular structure of the message and destabilize the cap binding complex. The message is then subject to degradation by either the exosome complex or the decapping complex. In this way, translationally inactive messages can be destroyed quickly, while active messages remain intact. The mechanism by which translation stops and the message is handed-off to decay complexes is not understood in detail. The majority of mRNA decay was believed to be cytoplasmic; however, recently, a novel mRNA decay pathway was described, which starts in the nucleus.
Sources: en.wikipedia.org
In the minor reaction pathway, a Prilezhaev epoxidation results in the formation of thiophene-2,3-epoxide that rapidly rearranges to the isomer thiophene-2-one. Trapping experiments demonstrate that this pathway is not a side reaction from the S-oxide intermediate, while isotopic labeling with deuterium confirm that a 1,2-hydride shift occurs and thus that a cationic intermediate is involved. If the reaction mixture is not anhydrous, this minor reaction pathway is suppressed as water acts as a competing base. Oxidation may be relevant to the metabolic activation of various thiophene-containing drugs, such as tienilic acid and the investigational anticancer drug OSI-930.
== Surgical procedure == TOPS is implanted following a lumbar decompression, in which bone and ligament tissue compressing the spinal nerves are removed. After decompression, the facet joints are excised and replaced with the TOPS implant. The goal is to preserve mobility at the treated level while preventing instability that would otherwise be addressed with spinal fusion.
== Ret design == An L-peptide has three analogue sequences (Figure 3) built from L and D amino acids: the D-enantiomer or inverso-peptide with the same sequence, but composed of D-amino acids and a mirror conformation; the retro-peptide, consisting of the same sequence of L amino acids but in reverse order; and the retro-inverso or D-retro-enantiomer peptide, consisting of D-amino acids in the reversed sequence. While the L-peptide and its D-enantiomer are mirror structures of each other, the L-retro-peptide is the mirror image of the D-retro-inverso-peptide. On the other hand, the L-peptide and the D-retro-inverso-peptide share a similar arrangement of side-chains, although their carboxyl and amino groups point in opposing directions. For small peptides that do not depend on a secondary structure for binding, an L-peptide and its D-retro-inverso-peptide is likely to have a similar binding affinity with a target L-protein.
=== Detection === Codeine and its major metabolites may be quantitated in blood, plasma, or urine to monitor therapy, confirm a diagnosis of poisoning, or assist in a medico-legal death investigation. Drug abuse screening programs generally test urine, hair, sweat or saliva. Many commercial opiate screening tests directed at morphine cross-react appreciably with codeine and its metabolites, but chromatographic techniques can easily distinguish codeine from other opiates and opioids. Codeine usage results in significant amounts of morphine as an excretion product. Furthermore, heroin contains codeine (or acetyl codeine) as an impurity and its use will result in the excretion of small amounts of codeine. Poppy seed foods represent yet another source of low levels of codeine in one's biofluids. Blood or plasma codeine concentrations are typically in the 50–300 μg/L range in persons taking the drug therapeutically, 700–7,000 μg/L in chronic users, and 1,000–10,000 μg/L in cases of acute fatal over dosage. Codeine is produced in the human body along the same biosynthetic pathway as morphine. Urinary concentrations of endogenous codeine and morphine have been found to significantly increase in individuals taking L-DOPA for the treatment of Parkinson's disease.
In the United States vaccination was regulated by individual states, the first to impose compulsory vaccination being Massachusetts in 1809. There then followed sequences of compulsion, opposition and repeal in various states. By 1930 Arizona, Utah, North Dakota and Minnesota prohibited compulsory vaccination, 35 states allowed regulation by local authorities, or had no legislation affecting vaccination, whilst in ten states, including Washington, D.C. and Massachusetts, infant vaccination was compulsory. Compulsory infant vaccination was regulated by only allowing access to school for those who had been vaccinated. Those seeking to enforce compulsory vaccination argued that the public good overrode personal freedom, a view supported by the U.S. Supreme Court in Jacobson v. Massachusetts in 1905, a landmark ruling which set a precedent for cases dealing with personal freedom and the public good. Louis T. Wright, an African-American Harvard Medical School graduate (1915), introduced, while serving in the Army during World War I, intradermal, smallpox vaccination for the soldiers.
Sources: en.wikipedia.org
IGN noted that both the controls and graphics of the Xbox 360 version are inferior to those of the PC version, in that switching between weapons or plasmids is easier using the PC's mouse than the 360's radial menu, as well as the graphics being slightly better with higher resolutions. The game has been touted as a hybrid first-person shooter, but two reviewers found advances from comparable games lacking, both in the protagonist and in the challenges he faces. Some reviewers also found the combat behavior of the splicers lacking in diversity (and their A.I. behavior not very well done), and the moral choice too much "black and white" to be interesting. Some reviewers and essayists such as Jonathan Blow also opined that the "moral choice" the game offered to the player (saving or harvesting the little sisters) was flawed because, to them, it had no real impact on the game, which ultimately led them to think that the sisters were just mechanics of no real importance. Daniel Friedman for Polygon concurred with Blow, noting that the player only loses 10% of the possible ADAM rewards for saving the Little Sisters rather than killing them, and felt that this would have been better instituted as part of the game difficulty mechanic.
Aroa Biosurgery Limited (formerly Mesynthes Limited) is a regenerative medicine company that develops, manufactures and distributes products for wound healing and soft tissue reconstruction. Aroa Biosurgery is headquartered in Auckland, New Zealand with a US office in San Diego, CA, and is listed on the Australian Securities Exchange (ASX: ARX). The company, originally known as Mesynthes Limited, was founded in 2008 by Veterinarian Surgeon Dr Brian Ward (BVSc). The company develops and commercializes products based on its proprietary ovine forestomach matrix technology platform with products in wound healing (Endoform, Natural, Endoform, Antimicrobial and Symphony) as well as plastics and reconstructive surgery (Myriad Matrix, Myriad Forme, Myriad Morcells, Ovitex PRS) and repair of hernia (Ovitex and Myriad Ultra).
This is a list of notable current and former fast food restaurant chain stores, as well as some fast casual restaurants, pizzerias (also see List of pizza chains), and coffeehouses (also see List of coffeehouse chains). See list here for ice cream parlors (see List of ice cream parlor chains).
=== Thermotherapy === For pain management, heat can be used to relieve stiffness, and cold can relieve muscle spasms and pain. The use of ice or cold packs may be beneficial; however, further research is needed. A 2003 Cochrane review of seven studies between 1969 and 1999 found ice massage to be of significant benefit in improving range of motion and function, though not necessarily relief of pain. Cold packs could decrease swelling, but hot packs did not affect swelling. Heat therapy could increase circulation, thereby reducing pain and stiffness, but with the risk of inflammation and edema. Another review found no evidence of benefit from placing hot packs on joints.
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.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.