TKPRPGP comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-12-07. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
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.
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.
=== News Sources === Collier, Ben (18 July 2013), Becoming More Like The Culture, No. 1: Economics (v0.1), archived from the original on 22 July 2013, retrieved 5 August 2013 Cross, Tim (31 March 2017), "The novelist who inspired Elon Musk", The Economist, archived from the original on 21 May 2017, retrieved 4 April 2017. Newitz, Annalee (27 March 2017), "Elon Musk is setting up a company that will link brains and computers", Ars Technica.
==== Impact on the environment ==== Post incineration process, toxic ash residue is produced and is often disposed at landfills. These landfills are not protected by any barrier and the residue has the potential of reaching underground water that is often exposed to human use. The combustion of plastic material releases toxic gases that escapes and joins breathable air. Human and animal exposure to such gases can cause long term breathing and health issues. The rotation of toxic air does not only impact human well-being, but also of animals and plants. Air pollution caused by the incinerators depletes the ozone layer, causes crop and forest damage, and increases the effects of climate change. Constant exposure to such toxins and chemicals in the air could be deemed detrimental to trees and plants and could eventually lead to extinction of certain plants in specific areas. Pollution and chemical leaks also affect the fruits of trees and would cause them to be poisonous and therefore inedible.
His discovery, made widely known through its financial success, greatly increased interest in organic chemistry. A crucial breakthrough for organic chemistry was the concept of chemical structure, developed independently in 1858 by both Friedrich August Kekulé and Archibald Scott Couper. Both researchers suggested that tetravalent carbon atoms could link to each other to form a carbon lattice, and that the detailed patterns of atomic bonding could be discerned by skillful interpretations of appropriate chemical reactions. The era of the pharmaceutical industry began in the last decade of the 19th century when the German company, Bayer, first manufactured acetylsalicylic acid—more commonly known as aspirin. By 1910 Paul Ehrlich and his laboratory group began developing arsenic-based arsphenamine (Salvarsan) as the first effective medicinal treatment of syphilis, and thereby initiated the medical practice of chemotherapy. Ehrlich popularized the concepts of "magic bullet" drugs and of systematically improving drug therapies. His laboratory made decisive contributions to developing antiserum for diphtheria and standardizing therapeutic serums.
The study of proteins in vivo is often concerned with the synthesis and localization of the protein within the cell. Although many intracellular proteins are synthesized in the cytoplasm and membrane-bound or secreted proteins in the endoplasmic reticulum, the specifics of how proteins are targeted to specific organelles or cellular structures is often unclear. A useful technique for assessing cellular localization uses genetic engineering to express in a cell a fusion protein or chimera consisting of the natural protein of interest linked to a "reporter" such as green fluorescent protein (GFP). The fused protein's position within the cell can then be cleanly and efficiently visualized using microscopy. Other methods for elucidating the cellular location of proteins requires the use of known compartmental markers for regions such as the ER, the Golgi, lysosomes or vacuoles, mitochondria, chloroplasts, plasma membrane, etc. With the use of fluorescently tagged versions of these markers or of antibodies to known markers, it becomes much simpler to identify the localization of a protein of interest. For example, indirect immunofluorescence will allow for fluorescence colocalization and demonstration of location. Fluorescent dyes are used to label cellular compartments for a similar purpose. Other possibilities exist, as well. For example, immunohistochemistry usually uses an antibody to one or more proteins of interest that are conjugated to enzymes yielding either luminescent or chromogenic signals that can be compared between samples, allowing for localization information.
Sources: en.wikipedia.org
=== Arthrochalasia === Arthrochalasia EDS (aEDS; formerly categorized as types 7A and B) is characterized by severe joint hypermobility and congenital hip dislocation. Other common features include fragile, elastic skin with easy bruising, hypotonia, kyphoscoliosis (kyphosis and scoliosis), and mild osteopenia. Type-I collagen is usually affected. It is very rare, with about 30 cases reported. It is more severe than the hypermobility type. Variations in the genes COL1A1 and COL1A2 cause it.
ColVI plays an important role in cancer by acting as a chemotherapy resistance modulator. ColVI inhibits oxidative damage and apoptosis. ColVI regulates cell differentiation and autophagic machinery. With the assistance of other collagens, proteoglycans, matrilineal, fibronectins, and glycoproteins, ColVI anchors the basement membrane of the skin to the extracellular matrix.
=== Steroids === A long-term course of corticosteroid injections into the scar may help flatten and soften the appearance of keloid or hypertrophic scars. Topical steroids are ineffective. However, clobetasol propionate can be used as an alternative treatment for keloid scars. Topical steroid applied immediately after fractionated CO2 laser treatment is however very effective (and more efficacious than laser treatment alone) and has shown benefit in numerous clinical studies.
== Research == Lemborexant is under development for the treatment of circadian rhythm sleep disorders, sleep apnea, and chronic obstructive pulmonary disease. As of February 2022, it is in phase 2 clinical trials for circadian rhythm sleep disorders and phase 1 trials for sleep apnea and chronic obstructive pulmonary disease.
"have a sensitivity of at least 80% for detecting a particular psychiatric disorder" "should have a specificity of at least 80% for distinguishing this disorder from other psychiatric or medical disorders" "should be reliable, reproducible, and ideally be noninvasive, simple to perform, and inexpensive" "proposed biomarkers should be verified by 2 independent studies each by a different investigator and different population samples and published in a peer-reviewed journal" The review concluded that although neuroimaging diagnosis may technically be feasible, very large studies are needed to evaluate specific biomarkers which were not available.
Sources: en.wikipedia.org
A geographic information system (GIS) can recognize and analyze the spatial relationships that exist within digitally stored spatial data. These topological relationships allow complex spatial modelling and analysis to be performed. Topological relationships between geometric entities traditionally include adjacency (what adjoins what), containment (what encloses what), and proximity (how close something is to something else).
White for hydrogen Black for carbon Sky blue for nitrogen Red for oxygen They also built smaller models using plastic balls with the same color schema. In 1965 Koltun patented an improved version of the Corey and Pauling modeling technique. In his patent he mentions the following colors:
The first and innermost major ring, Bulvarnoye Koltso (Boulevard Ring), was built on the former location of the 16th-century city wall around Bely Gorod (White Town). The Bulvarnoye Koltso is technically not a ring: it forms an incomplete circle—a horseshoe-shaped arc beginning at the Cathedral of Christ the Saviour and ending at the Yauza River. The second primary ring, located outside the Boulevard Ring, is the Sadovoye Koltso (Garden Ring). Like the Boulevard Ring, the Garden Ring follows the path of a 16th-century wall that previously encompassed part of Moscow. The Third Ring Road was completed in 2003 as a high-speed freeway. The Fourth Transport Ring—another freeway—was planned, but it was canceled in 2011. A system of chordal highways will be constructed instead. In addition to these concentric ring roads, line 5 of the Moscow Metro is circular (hence its name Koltsevaya Liniya [lit. 'ring line']). It is located between the Garden Ring and the Third Transport Ring. Two overlapping lines of the Moscow Metro form "two hearts":t
An analysis of GPX1 expression in oligodendrocytes from patients with major depressive disorder and control patients showed that GPX1 levels were significantly decreased in patients with the disorder, but not in their astrocytes. Shortening of telomeres and decreased expression of telomerase were also evident in these oligodendrocytes, but not in the astrocytes in these patients. This suggests that decreased oxidative stress protection, as observed by decreased GPX1 levels, and decreased telomerase expression may help give rise to telomere shortening in patients with MDD.
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.
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.