If you have been reading about Selank and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-05-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
| 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 |
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
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.
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.
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.
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.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
=== EttA === EttA (Energy-dependent translational throttle A) is an ATP-binding protein of the ABC-F family which is thought to modulate translation rate based on the energy level of a cell. When ADP (degraded ATP, indicating low energy) levels are high, the protein inhibits ribosome activity, allowing translation at high ATP levels. EttA interferes specifically after the formation of the first peptide bond in the new protein and before the first translocation step induced by EF-G.
When the U.S. government created the United States Agency for International Development (USAID) in November 1961, it built on a legacy of previous development-assistance agencies and their people, budgets, and operating procedures. USAID's predecessor agency was already substantial, with 6,400 U.S. staff in developing-country field missions in 1961. Except for the peak years of the Vietnam War, 1965–70, that was more U.S. field staff than USAID would have in the future, and triple the number USAID has had in field missions in the years since 2000. Although the size of the development-assistance effort was not new, the 1961 decision to reorganize the government's main development-assistance agency was a landmark in terms of institutional evolution, representing the culmination of twenty years' experience with different organizational forms and procedures, in changing foreign-policy environments. The new structure created in 1961 "proved to be sturdy and durable". In particular, the U.S. government has maintained since then "the unique American pattern of placing strong resident aid missions in countries that [the U.S. was] helping." The story of how the base for USAID's structure was built is described below, along with an account of changes that have been made since 1961.
It often happens that the amount of antibody available to the researcher for their immunoprecipitation experiment is less than sufficient to saturate the agarose beads to be used in the immunoprecipitation. In these cases the researcher can end up with agarose particles that are only partially coated with antibodies, and the portion of the binding capacity of the agarose beads that is not coated with antibody is then free to bind anything that will stick, resulting in an elevated background signal due to non-specific binding of lysate components to the beads, which can make data interpretation difficult. While some may argue that for these reasons it is prudent to match the quantity of agarose (in terms of binding capacity) to the quantity of antibody that one wishes to be bound for the immunoprecipitation, a simple way to reduce the issue of non-specific binding to agarose beads and increase specificity is to preclear the lysate, which for any immunoprecipitation is highly recommended.
The researchers have mentioned that part of the liquid-disorder formation occurs possibly be interrupting the hydrophobic region of the phospholipids, by binding closely towards the hydrophilic region of the phospholipid, and acting as "filler" since ethanol cannot closely align with the neighboring phospholipids. All of these possible mechanisms can be contributed to ethanol's amphiphilic nature.
== Arrests == On 13 July 2011, operations chief and one of the founders of the organization, Martin Arzola Ortega, was arrested. On 7 August 2012, it was announced that Ortega's successor, Eliot Alberto Radillo Peza, was captured in Zapopan, Jalisco. At the time of Peza's arrest, it was announced that twelve suspected members of the Jalisco Nueva Generacion cartel, including leaders Martin Arzola and Abundio Mendoza Gaytan, had been arrested since July 2011 on extortion, kidnapping and drug charges. On 9 March 2012, another founder of the organization, Érick Valencia Salazar, alias El 85, was captured by the Mexican Army along with another high-ranking lieutenant in Zapopan, Jalisco. Their apprehensions prompted over a dozen blockades throughout the city. 26 public transportation buses were burned with gasoline and then used to block the city streets. More than 30 assault rifles, grenades, cartridges, and ammunition magazines were confiscated. Felipe Calderón, the president of Mexico, congratulated the Mexican army for the capture of Érick Valencia Salazar. The Matazetas (CJNG) later apologized for the blockades by putting up several banners throughout the Guadalajara metropolitan area. They wrote that the blockades were "only a reaction for messing with their CJNG companion", who reportedly dedicated his work to "maintain tranquility in the state of Jalisco." On 18 March 2012, José Guadalupe Serna Padilla, another ranking lieutenant in the cartel, was captured along with another cartel member as well.
Sources: en.wikipedia.org
=== Grafting techniques === Grafting copolymers to a surface can be envisioned as fixing polymeric chains to a structurally different polymer substrate with the intention of changing surface functionality while preserving bulk mechanical properties. The nature and degree of surface functionalization is determined by both the choice of copolymer and the type and extent of grafting.
Three groups of enzymes (prolyl-3-hydroxylases, prolyl-4-hydroxylases, and lysyl hydroxylases) that are required for the hydroxylation of proline and lysine in the synthesis of collagen. These reactions add hydroxyl groups to the amino acids proline or lysine in the collagen molecule via prolyl hydroxylase and lysyl hydroxylase, both requiring vitamin C as a cofactor. The role of vitamin C as a cofactor is to oxidize prolyl hydroxylase and lysyl hydroxylase from Fe2+ to Fe3+ and to reduce it from Fe3+ to Fe2+. Hydroxylation allows the collagen molecule to assume its triple helix structure, and thus vitamin C is essential to the development and maintenance of scar tissue, blood vessels, and cartilage. Two enzymes (ε-N-trimethyl-L-lysine hydroxylase and γ-butyrobetaine hydroxylase) are necessary for synthesis of carnitine. Carnitine is essential for the transport of fatty acids into mitochondria for ATP generation. Hypoxia-inducible factor-proline dioxygenase enzymes (isoforms: EGLN1, EGLN2, and EGLN3) allows cells to respond physiologically to low concentrations of oxygen. Dopamine beta-hydroxylase participates in the biosynthesis of norepinephrine from dopamine. Peptidylglycine alpha-amidating monooxygenase amidates peptide hormones by removing the glyoxylate residue from their c-terminal glycine residues. This increases peptide hormone stability and activity. As an antioxidant, ascorbate scavenges reactive oxygen and nitrogen compounds, thus neutralizing the potential tissue damage of these free radical compounds.
Extremely strong: Histamine H1 receptor Strong: α1-adrenergic receptor, 5-HT2A and muscarinic acetylcholine receptors Moderate: 5-HT2C and 5-HT1A receptors Weak: α2-adrenergic and D2 receptors Based on its IC50Tooltip half-maximal inhibitory concentration values for monoamine reuptake inhibition, doxepin is relatively selective for the inhibition of norepinephrine reuptake, with a much weaker effect on the serotonin transporter. Although there is a significant effect that takes place at one of the specific serotonergic binding sites, the 5-HT2A serotonin receptor subtype. There is negligible influence on dopamine reuptake. The major metabolite of doxepin, nordoxepin (desmethyldoxepin), is pharmacologically active similarly, but relative to doxepin, is much more selective as a norepinephrine reuptake inhibitor. In general, the demethylated variants of tertiary amine TCAs like Nortriptyline, Desipramine and nordoxepin are much more potent inhibitors of norepinephrine reuptake, less potent inhibitors of serotonin reuptake, and less potent in their antiadrenergic, antihistamine, and anticholinergic activities. Antidepressant doses of doxepin are defined as 25 to 300 mg/day, although are typically above 75 mg/day. Antihistamine doses, including for dermatological uses and as a sedative/hypnotic for insomnia, are considered to be 3 to 25 mg, although higher doses between 25 and 50 mg and in some cases even up to 150 mg have been used to treat insomnia. At low doses, below 25 mg, doxepin is a pure antihistamine and has more of a sedative effect.
The MMR vaccine (abbreviated as MMR) is a combination vaccine against measles, mumps, and rubella (German measles). It contains the combined measles vaccine, mumps vaccine, and rubella vaccine into a single injection. After two doses, 97% of people are protected against measles, 88% against mumps, and at least 97% against rubella. The vaccine is also recommended for those who do not have evidence of immunity, those with well-controlled HIV/AIDS, and within 72 hours of exposure to measles among those who are incompletely immunized. It is given by injection. Measles is a highly contagious viral illness that can lead to serious complications, including pneumonia, acute encephalitis, and, in rare cases, long‑term neurological disease. Pregnant women are at increased risk of severe respiratory complications and adverse pregnancy outcomes such as pregnancy loss and premature birth. The MMR vaccine is widely used around the world. As of 2012, 575 million doses had been administered since the vaccine's introduction worldwide. Measles resulted in 2.6 million deaths per year before immunization became common. This has decreased to 122,000 deaths per year as of 2012, mostly in low-income countries. Through vaccination, as of 2018, rates of measles in North and South America are very low. Rates of disease have been seen to increase in populations that go unvaccinated. Between 2000 and 2018, vaccination decreased measles deaths by 73%. Side effects of immunization are generally mild and resolve without any specific treatment.
== See also == Anti-Chilean sentiment Chile–Peru relations Chilenization of Tacna, Arica, and Tarapacá Colombianization of Leticia, Putumayo and Caquetá Ecuadorian–Peruvian territorial dispute Indigenous peoples and the War of the Pacific
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 seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.