If you have been reading about Enkephalinase 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.
Updated 2025-11-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
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 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.
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.
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.
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.
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.
Moslift, one of the city's major elevator operators, has about 1,500 mechanics on call to respond when residents become trapped. Stalinist-era buildings, mostly found in the central part of the city, are large and usually ornamented with Socialist realism motifs that imitate classical themes. However, small churches—almost always Eastern Orthodox—around the city evoke its past. The Old Arbat Street, a tourist street that was once the center of a bohemian area, retains most of its buildings from before the 20th century. Many buildings found on the inner city's side streets (behind the Stalinist façades of Tverskaya Street, for example) provide examples of bourgeois architecture typical of Tsarist times. Ostankino Palace, Kuskovo, Uzkoye, and other large estates just outside Moscow originally belonged to nobles during the Tsarist era. Some convents and monasteries, both inside and outside the city, are open to Muscovites and tourists.
=== Pre-modern === The earliest descriptions of the coronary and pulmonary circulation systems can be found in the Commentary on Anatomy in Avicenna's Canon, published in 1242 by Ibn al-Nafis. In his manuscript, al-Nafis wrote that blood passes through the pulmonary circulation instead of moving from the right to the left ventricle as previously believed by Galen. His work was later translated into Latin by Andrea Alpago. In Europe, the teachings of Galen continued to dominate the academic community and his doctrines were adopted as the official canon of the Church. Andreas Vesalius questioned some of Galen's beliefs of the heart in De humani corporis fabrica (1543), but his magnum opus was interpreted as a challenge to the authorities and he was subjected to a number of attacks. Michael Servetus wrote in Christianismi Restitutio (1553) that blood flows from one side of the heart to the other via the lungs.
Methods incorporating chromatography generally begin with cryo-depleted plasma undergoing buffer exchange via either diafiltration or buffer exchange chromatography, to prepare the plasma for following ion exchange chromatography steps. After ion exchange, generally purification steps and buffer exchange occur. However, chromatographic methods began to be adopted in the 1980s. Developments were ongoing between when Cohn fractionation started emerge in 1946, and when chromatography emerged, in 1983. In 1962, the Kistler and Nistchmann process was created as a spin-off of the Cohn process. In the 1990s, the Zenalb and the CSL Albumex processes were created, which incorporated chromatography with variations. The general approach to using chromatography for plasma fractionation for albumin is: recovery of supernatant I, delipidation, anion exchange chromatography, cation exchange chromatography, and gel filtration chromatography. The recovered purified material is formulated with combinations of sodium octanoate and sodium N-acetyl tryptophanate and then subjected to viral inactivation procedures, including pasteurization at 60 °C. This is a more efficient alternative than the Cohn process because:
Sources: en.wikipedia.org
==== Sleep ==== Sleep disturbances are seen as a possible risk factor for inflammation in Alzheimer's disease. Sleep disruption was previously only seen as a consequence of Alzheimer's disease, but as of 2020, accumulating evidence suggests that this relationship may be bidirectional.
== Epidemiology == Sydenham's chorea is primarily seen in children. As with rheumatic fever, Sydenham's chorea is seen more often in less affluent communities, whether in the developing world or in aboriginal communities in the global North. High rates of impetigo are a marker for widespread streptococcal transmission. In the UK, there are approximately 20 cases per year, according to a BPSU surveillance study.
== Gliding scandals == During the 2020 Women's World Gliding Championships at Lake Keepit, Australia, the home team captain Terry Cubley (Executive Officer of the GFA) was charged with unsporting behaviour for hacking the official tracking system to bypass the mandatory 15 minute delay and forward real time competitors' positions to his team, granting a tactical advantage. An investigation revealed that Matt Gage had been closely involved with the developers of the tracking system, and was aware of an undocumented back door that allowed the team captain (Terry Cubley) to bypass the 15 minute delay. This real-time information was relayed by the team captain over the radio to the Australian pilots. This was the first time in the sport's history that an entire team had been penalised for unsporting behaviour, with the Competition Director applying a penalty of 25 points per pilot per day. Controversially the pilots involved were spared disqualification only receiving a relatively trivial points reduction (compared to a competing pilot who was disqualified for infringing airspace earlier in the competition). Following a subsequent GFA investigation two of the Australian Team admitted to cheating and the GFA made a formal apology to the FAI and the wider gliding community. Terry Cubley was removed from his role as Vice President of the IGC, but chose to remain as Executive Officer of the GFA . The pilots involved chose to appeal against this decision, resulting in the longest and most comprehensive investigation in the FAIs history.
Despite urges for increased financial support, the UPP units amassed praise in their early years for evident decreases in both visible crime and violence within the favelas they were operating in. Because military presence was a precursor to actual UPP units, many drug traffickers fled occupied favelas to avoid persecution or capture by the Military Police tactical unit, BOPE. Because of this, crime rates significantly dropped for a couple years. In interviews with residents, details of the freedoms they were allowed once UPP units were installed continued to highlight the successes of the project.
Sources: en.wikipedia.org
Market Place (formerly Market Place by Jasons, Jason's Food & Living, and Jasons ichiba) in Hong Kong is a high-end supermarket chain owned by DFI Retail Group. The chain also has a joint venture in mainland China with Beijing Hualian Group called BHG Market Place and formerly ran stores (Jasons Market Place) in Taiwan until they were sold to Carrefour. The Malaysian chain called Mercató (formerly Jasons Food Hall) is owned by Macrovalue Sdn Bhd. after its acquisition of DFI Malaysian food retailing business in 2023. Cold Storage Fresh (formerly Market Place, Jasons, and Jasons Deli) in Singapore is also owned by Macrovalue Sdn Bhd since 2025. The Marketplace (formerly Market Place by Rustan's) in the Philippines has been owned by Robinsons Retail Holdings since 2018, before which it was owned by Rustan Supercenters. DFI also operates further similar supermarkets under the 3hreeSixty and Oliver's The Delicatessen brands in Hong Kong and other supermarkets around Asia with Wellcome.
Alginic acid, also called algin, is a naturally occurring, edible polysaccharide found in brown algae. It is hydrophilic and forms a viscous gum when hydrated. When the alginic acid binds with sodium and calcium ions, the resulting salts are known as alginates. Its colour ranges from white to yellowish-brown. It is sold in filamentous, granular, and powdered forms. It is a significant component of the biofilms produced by the bacterium Pseudomonas aeruginosa, a major pathogen found in the lungs of some people who have cystic fibrosis. The biofilm and P. aeruginosa have a high resistance to antibiotics, but are susceptible to inhibition by macrophages. Alginate was discovered by the British chemical scientist E. C. C. Stanford in 1881, and he patented an extraction process for it in the same year. The alginate was extracted, in the original patent, by first soaking the algae in water or diluted acid. The resulting insoluble alginic acid is then treated with an alkaline solution such as sodium carbonate, creating sodium alginate, before finally precipitating and purifying the alginate from solution.
===== MeSH D08.811.682.667 – oxidoreductases acting on sulfur group donors ===== MeSH D08.811.682.667.061 – dihydrolipoamide dehydrogenase MeSH D08.811.682.667.076 – ferredoxin-nadp reductase MeSH D08.811.682.667.092 – glutathione reductase MeSH D08.811.682.667.124 – hydrogensulfite reductase MeSH D08.811.682.667.186 – protein-disulfide reductase (glutathione) MeSH D08.811.682.667.217 – sulfite dehydrogenase MeSH D08.811.682.667.249 – sulfite oxidase MeSH D08.811.682.667.374 – sulfite reductase (ferredoxin) MeSH D08.811.682.667.500 – sulfite reductase (nadph) MeSH D08.811.682.667.750 – thioredoxin reductase (nadph)
Sources: en.wikipedia.org
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.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
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.