A practical reference on Enkephalinase: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-04. Anything still debated is marked as such rather than presented as settled.
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.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
| 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 |
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.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
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.
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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
== Etymology == The English word frankincense derives from the Old French expression franc encens, meaning 'true incense', maybe with the sense of 'high quality incense'. The adjective franc in Old French meant 'noble, true', in this case perhaps 'pure'; although franc is ultimately derived from the tribal name of the Franks, it is not a direct reference to them in the word frankincense. The word for frankincense in the Koine Greek of the New Testament, λίβανος, líbanos (or λιβανωτός, libanōtós), is cognate with the name of Lebanon (Greek: Λίβανος); the same can be said with regard to Arabic, Phoenician, Hebrew, and Vulgar Latin: lĭbănus. This is postulated to be because they both derive from the word for 'white' and that the spice route went via Mount Lebanon (Koine Greek: Λίβανος, romanized: Libanos). Medieval Latin: olibanum derived from λίβανος or libanus. The leading "o" may have come from Latin: oleum, lit. 'oil', or from the Greek article o- or Arabic article al-. Other names include Arabic: اللبان, romanized: al-lubān, Persian: کندر, romanized: kondor, Syriac: בוּסמִין, romanized: busmin, Hebrew: לבונה, romanized: ləvonā, Bengali: লোবান, ধুনো, romanized: lōban, dhunō, Somali: foox (fooḥ), Turkish: akgünlük, Classical Latin: tūs.
2019 Ford EcoBoost 400 – in the final race of the 2019 Monster Energy NASCAR Cup Series, three teams – Premium Motorsports, Spire Motorsports and Rick Ware Racing – were found to have manipulated the race finish by parking their cars in order to allow the No. 27 team to score more points, passing the Gaunt Brothers Racing No. 96 in the standings to obtain an end of season cash bonus.
== History == Crisaborole was developed by Anacor Pharmaceuticals for the topical treatment of psoriasis. During preclinical and clinical development, crisaborole was called AN2728 and PF-06930164. The drug was assumed to be potential $2bn-a-year blockbuster, when Pfizer acquired Anacor Pharmaceuticals. However, the drug was commercially not successful, reaching only US$147 million in sales in 2018, and US$138 million in sales in 2019. Crisaborole was approved for use in the United States in December 2016 and for use in Canada in June 2018. The safety and efficacy of crisaborole were established in two placebo-controlled trials with a total of 1,522 participants ranging in age from two years of age to 79 years of age, with mild to moderate atopic dermatitis. In both trials participants received treatment with either crisaborole or placebo twice daily for 28 days. Neither the participants nor the health care providers knew which treatment was being given until after the trials were completed. Overall, participants receiving crisaborole achieved greater response with clear or almost clear skin after 28 days of treatment. The trials were conducted in the US. Crisaborole, approved for the treatment of mild to moderate atopic dermatitis in the European Union, has been rapidly withdrawn from the European market (March 2020 - February 2022).
Sources: en.wikipedia.org
=== Health facilities === Another possible long-term solution to malnutrition is to increase access to health facilities in rural parts of the world. These facilities could monitor undernourished children, act as supplemental food distribution centers, and provide education on dietary needs. Similar facilities have already proven very successful in countries such as Peru and Ghana.
The rapid Anglo-Norman conquest proved more important than it seemed. The island occupied a key strategic position on the maritime lanes to the Holy Land, whose occupation by the Christians could not continue without support from the sea. Shortly after the conquest, Cyprus was sold to the Knights Templar and it was subsequently acquired, in 1192, by Guy de Lusignan and became a stable feudal kingdom. It was only in 1489 that the Venetians acquired full control of the island, which remained a Christian stronghold until the fall of Famagusta in 1571.
=== Compounds === Magnesium compounds, primarily magnesium oxide (MgO), are used as a refractory material in furnace linings for producing iron, steel, nonferrous metals, glass, and cement. Magnesium oxide and other magnesium compounds are also used in the agricultural, chemical, and construction industries. Magnesium oxide from calcination is used as an electrical insulator in fire-resistant cables. Magnesium reacts with haloalkanes to give Grignard reagents, which are used for a wide variety of organic reactions forming carbon–carbon bonds. Magnesium salts are included in various foods, fertilizers (magnesium is a component of chlorophyll), and microbe culture media. Magnesium sulfite is used in the manufacture of paper (sulfite process). Magnesium phosphate is used to fireproof wood used in construction. Magnesium hexafluorosilicate is used for moth-proofing textiles.
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.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.