Enkephalinase raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-05. Anything still debated is marked as such rather than presented as settled.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
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.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
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.
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.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
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.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
However, most contemporary accounts agree that the ANC's presence in South African townships during the mid-1980s was sparse and was vastly insufficient to instigate or direct events. Thula Simpson, a historian of the ANC, says that the ANC was largely a "spectator" in the first year of the uprising, though an interested spectator. Mac Maharaj, a senior ANC official, later said that the Vaal uprising had provided a lesson for the ANC precisely because it "took place in a power vacuum. We were not ready or able to exploit fully the potential unleashed by these uprisings." Some historians argue that the ANC did not accelerate its "ungovernability" strategy until 1985, by which time the strategy was little more than an attempt to "place the ANC at the head of an [already] unfolding social revolution". However, the ANC was not so far removed as to be without influence. At least two founding members of the VCA were members of an underground ANC cell, and some militant youth cells received a degree of training from the ANC's armed wing, MK, or from MK alumni, though this rarely amounted to the full military training that recruits received in MK camps abroad. From 1985, MK cadres began to bring a small number of weapons, such as rifles and hand grenades, to the Vaal area. More significantly, many township activists supported and identified with the ANC. This was particularly the case with militant youths, who, for example, appropriated the symbols of MK's guerrilla war, and who in some cases viewed their local organisations as unofficial cells of MK.
== Function == The primary function of DPEP1 is to hydrolyze various dipeptides in renal metabolism. Specifically, it has been found to hydrolyze glutathione and its conjugates such as leukotriene D (Kozak and Tate, 1982). Several pieces of evidence suggest that DPEP1 is also responsible for the hydrolysis of the beta-lactam ring of various THM-class antibiotics, such as penem and carbapenem (Campbell et al., 1984). First, the metabolism of these THM-class antibiotics is known to be localized in the kidney, specifically by a membrane-bound protein. Second, the metabolism of these antibiotics is significantly hindered when the zinc concentration is altered, suggesting the enzyme responsible for the drugs’ metabolism is a zinc-metalloenzyme. Finally, when DPEP1 was experimentally added to penem and carbapenem antibiotics in vitro, the resulting products were structurally identical to their respective metabolites found in an organism's urine (8). The hydrolysis of these antibiotics hinders their antibacterial capabilities, so information on the specific structure of DPEPI is highly sought after in order to find viable inhibitors that could be taken along with these antibiotics to make them more effective. Earlier, beta-lactamase enzymes were thought to occur only in bacteria, where their probable function was in protecting the organisms against the action of beta-lactam antibiotics. These antibiotics exhibit selective toxicity against bacteria but virtual inertness against many eukaryotic cells (Adachi et al., 1990).[supplied by OMIM]
In order to reach the maximum efficacy to eradicate biofilms, therapeutic strategies need to target both the biofilm matrix components as well as the embedded microorganisms to target the complex biofilm microenvironment.
First, it had several interesting things happen in it, all triggered by the player rather than a timer so that the player would set the pace of the level. Second, the level responded to any player action, even for something as simple as adding graphic decals to wall textures to show a bullet impact. Finally, the level warned the player of imminent danger to allow them to avoid it, rather than killing the player with no warning. To move forward with this unified design, Valve sought a game designer but found no one suitable. Instead, Valve created the "cabal", initially a group of six individuals from across all departments that worked primarily for six months straight in six-hour meetings four days a week. The cabal was responsible for all elements of design, including level layouts, key events, enemy designs, narrative, and the introduction of gameplay elements relative to the story. The collaboration proved successful, and once the cabal had come to decisions on types of gameplay elements that would be needed, mini-cabals from other departments most affected by the choice were formed to implement these elements. Membership in the main cabal rotated since the required commitment created burnout.
The chief cells of the parathyroid glands sense the amount of calcium in the blood, and release the calcium-increasing hormone parathyroid hormone (PTH) accordingly to correct or maintain normal blood calcium levels. It therefore regulates calcium metabolism as part of the endocrine system. PTH raises calcium levels by releasing calcium from bone storage, as well as retaining calcium from the urine, and alerts the intestines to absorb more calcium from ingested nutrients. Too much of either hormone can be an indicator of disease.
Sources: en.wikipedia.org
Saint Kitts and Nevis - The Scout Association of Saint Kitts and Nevis* Tonga - Tonga branch of The Scout Association* Tuvalu - Tuvalu Scout Association* Vanuatu - Vanuatu branch of The Scout Association* Served by Scouts Australia
In 2021, global fish production reached 182 million tonnes, with approximately equal amounts coming from capture (91.2 million tonnes) and aquaculture (90.9 million tonnes). Aquaculture has experienced rapid growth in recent decades, increasing almost sevenfold from 1990 to 2021.
During the Napoleonic Wars, the United States, Sweden, and Sicily fought against the Barbary pirates in the Mediterranean. The Barbary wars were a conflict between the United States and the North African States (Tripoli, Algiers, Tunis, and Morocco).
=== MeSH D12.644.641 – peptides, cyclic === MeSH D12.644.641.040 – alamethicin MeSH D12.644.641.050 – amanitins MeSH D12.644.641.075 – bacitracin MeSH D12.644.641.142 – capreomycin sulfate MeSH D12.644.641.235 – cyclosporins MeSH D12.644.641.235.300 – cyclosporine MeSH D12.644.641.243 – cyclotides MeSH D12.644.641.252 – dactinomycin MeSH D12.644.641.270 – daptomycin MeSH D12.644.641.297 – depsipeptides MeSH D12.644.641.297.500 – valinomycin MeSH D12.644.641.325 – echinomycin MeSH D12.644.641.380 – ferrichrome MeSH D12.644.641.515 – mycobacillin MeSH D12.644.641.548 – nanotubes, peptide MeSH D12.644.641.582 – nisin MeSH D12.644.641.650 – octreotide MeSH D12.644.641.735 – phalloidine MeSH D12.644.641.780 – polymyxins MeSH D12.644.641.780.110 – colistin MeSH D12.644.641.780.750 – polymyxin b MeSH D12.644.641.802 – streptogramins MeSH D12.644.641.802.249 – mikamycin MeSH D12.644.641.802.374 – pristinamycin MeSH D12.644.641.802.500 – streptogramin group a MeSH D12.644.641.802.500.500 – streptogramin a MeSH D12.644.641.802.750 – streptogramin group b MeSH D12.644.641.802.750.500 – streptogramin b MeSH D12.644.641.802.812 – vernamycin b MeSH D12.644.641.802.875 – virginiamycin MeSH D12.644.641.802.875.500 – streptogramin a MeSH D12.644.641.825 – thiostrepton MeSH D12.644.641.875 – viomycin MeSH D12.644.641.875.250 – enviomycin
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
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.