If you have been reading about Research chemical 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 2026-01-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
=== Importance === GGC is essential to mammalian life. Mice that have had the glutamate-cysteine ligase (GCL) gene knocked out do not develop beyond the embryo stage and die before birth. This is because GGC is vital for the biosynthesis of glutathione. Since the production of cellular GGC in humans slows down with age, as well as during the progression of many chronic diseases, it has been postulated that supplementation with GGC could offer health benefits. Such GGC supplementation may also be of benefit in situations where glutathione has been acutely lowered below optimum, such as following strenuous exercise, during trauma or episodes of poisoning. Several review articles have been published exploring the therapeutic potential of GGC to replenish glutathione in age-related and chronic disease states such as Alzheimer's disease. GGC also shows antioxidant properties.
==== MeSH E05.337.550 – drug evaluation, preclinical ==== MeSH E05.337.550.200 – drug screening assays, antitumor MeSH E05.337.550.200.800 – tumor stem cell assay MeSH E05.337.550.200.900 – xenograft model antitumor assays MeSH E05.337.550.200.900.830 – subrenal capsule assay MeSH E05.337.550.400 – microbial sensitivity tests MeSH E05.337.550.400.800 – serum bactericidal test MeSH E05.337.550.600 – parasitic sensitivity tests
===== Nuclear Magnetic Resonance ===== To analyze the full structure of a nascent polypeptide, nuclear magnetic resonance (NMR) is used. NMR allows a dynamic view of molecules in solution and so can be used on ribosome-nascent chain complexes (RNC). Labelling of ribosomes allows the NMR data to be filtered for suspected ribosome signal and identify the signal of the nascent polypeptide.
The UK's first supermarket under the new Premier Supermarkets brand opened in Streatham, South London, taking in ten times as much revenue per week as the average British general store of the time. Other chains caught on quickly. The number of British supermarkets exploded from roughly 50 in 1950 to 572 by 1961, and finally to over 3,400 by 1969. After Galvani lost out to Tesco's Jack Cohen in 1960 to buy 212 stores of the Irwin's chain, the sector underwent significant consolidation, resulting in "the big four" dominant UK supermarket chains: Tesco, Asda, Sainsbury's and Morrisons. In the 1950s, supermarkets frequently issued trading stamps as incentives to customers. Today, most chains issue store-specific "membership cards", "club cards", or "loyalty cards". These typically enable the cardholder to receive special members-only discounts on certain items when the credit card-like device is scanned at the checkout. Sales of selected data generated by club cards is becoming a significant revenue stream for some supermarkets.
Sources: en.wikipedia.org
Early flowering: Single Early Tulips, Double Early Tulips, Greigii Tulips, Kaufmanniana Tulips, Fosteriana Tulips, Species Tulips Mid-season flowering: Darwin Hybrid Tulips, Triumph Tulips, Parrot Tulips Late season flowering: Single Late Tulips, Double Late Tulips, Viridiflora Tulips, Lily-flowering Tulips, Fringed (Crispa) Tulips, Rembrandt Tulips
=== Diseases === Verticillium wilt is a major constraint in peppermint cultivation. 'Todd's Mitcham', 'Refined Murray', 'Roberts Mitcham' (see above), and a few other cultivars have some degree of resistance.
In 1794, Johann Peter Frank gave a relatively clear description of diabetes insipidus, as a "long continued abnormally increased secretion of non-saccharine urine which is not caused by a diseased condition of the kidneys". This remained the general state of knowledge for another century. William Osler, in the first edition of his textbook (1892), summarized the pathophysiology of the condition as follows: "The nature of the disease is unknown. It is doubtless of nervous origin. The most reasonable view is that it results from a vasomotor disturbance of the renal vessels... giving rise to continuous renal congestion."
Copper IUDs acts as a spermicide. Copper ions released from the IUD damage sperm and disrupt their ability to move, preventing sperm from traveling through the cervical mucus or destroying them as they pass through so that they never meet the egg. They also start a local inflammatory reaction that causes the uterus and fallopian tubes to produce a fluid that contains white blood cells, enzymes, and prostaglandins, which are toxic to sperm. While not the main mechanism of action, studies have found that copper can also alter the endometrial (uterine) lining. This alteration can prevent implantation of a fertilized egg ("blastocyst"), but it cannot disrupt a fertilized egg that has already been implanted in the uterine lining.
In March 1917, the abdication of Tsar Nicholas II led to the Russian Provisional Government (March–July 1917), who then proclaimed the Russian Republic (September–November 1917). Later in the October Revolution, the Bolshevik's seizure of power against the Provisional Government resulted in their establishment of the Russian Soviet Federative Socialist Republic (1917–1991), yet parts of Russia remained occupied by the counter-revolutionary White Movement of anti-communists who had united to form the White Army to fight the Russian Civil War (1917–1922) against the Bolshevik government. Moreover, despite the White–Red civil war, Russia remained a combatant in the Great War that the Bolsheviks had quit with the Treaty of Brest-Litovsk which then provoked the Allied Intervention to the Russian Civil War by the armies of seventeen countries, featuring Great Britain, France, Italy, the United States and Imperial Japan.
Sources: en.wikipedia.org
== Biosynthesis == A novel aspect of PQQ is its biosynthesis in bacteria from a ribosomally translated precursor peptide, PqqA. A glutamic acid and a tyrosine in PqqA are cross-linked by the radical SAM enzyme PqqE with the help of PqqD in the first step of PqqA modification. A protease then liberates the Glu-Tyr molecule from the peptide backbone. PqqB oxidizes the 2 and 3 positions on the tyrosine ring, forming a quinone which quickly becomes AHQQ, finishing the pyridine ring. PqqC then forms the final pyrrole ring.
== Treatment == Avoid cold weather. Treat the underlying lymphoma. No cold drinks; all drinks should be at room temperature (or above). Requires heater to maintain temperature in cold places. Treatment with rituximab has been described. The treatment of cold agglutinin disease depends on many factors including the severity of the condition, the signs and symptoms present in each person, and the underlying cause. For example, in those affected by secondary cold agglutinin disease, it is important to diagnose and treat the underlying condition which may include certain types of cancer; bacterial, viral, or parasitic infections; and/or other autoimmune disease. People with few symptoms and/or mild anemia may not require any specific treatment. These cases are often managed by simply avoiding exposure to the cold. In severe cases of hemolysis, medical interventions may be necessary. Rituximab (an antibody that selectively reduces specific types of immune cells) is effective in about 60% of cases of severe cold agglutinin disease. Medical researchers have found the response to rituximab is seen on average within 1 to 2 months of treatment and the effect of the treatment lasts for about 1 to 2 years. Rituximab may be used after a second and even a third relapse, however the success rate is less. Combined treatment with rituximab and fludarabine has resulted in higher response rates (76% of cases) and longer periods of remissions (on average, 6.5 years).
Most of the high or low affinity bindings require chelation or competitive titration. This method is done by loading pre-bound complex solution in the sample cell and chelating one of the components out with a reagent of higher observed binding affinity within the desirable c-window. In order to ensure optimum instrument stability, the ITC instrument should be powered on at least one day before use. Samples should ideally be pre-equilibrated to approximately 2 °C below the target experimental temperature to reduce stabilization time after loading, although starting at the exact experimental temperature is also an option. For instrument cleaning, sample cell should be rinsed with the experimental buffer and dried under vacuum, and any remaining rinsed solution should be discarded manually with a syringe. Then, the sample cell is filled with the experimental solution and the reference cell with either high-purity water or the same buffer. To prevent air contamination, gas-tight Hamilton syringes are used, ensuring the needle is positioned near the bottom of the sample cell before dispensing the liquid slowly. Experimental parameters such as the number of injections, initial injection volume, subsequent injection volumes, temperature, reference power, stirring speed, spacing, initial delay, and filter period should be adjusted according to the specific study. If the experiment is to be repeated, the syringe should be emptied, with the solution either discarded or saved for further analysis.
=== International Organization for Standardization (ISO) === According to the International Organization for Standardization (ISO) technical specification 80004, a nanoparticle is an object with all three external dimensions in the nanoscale, whose longest and shortest axes do not differ significantly, with a significant difference typically being a factor of at least 3.
S-adenosyl-L-homocysteine + protein L-glutamate methyl ester Thus, the two substrates of this enzyme are S-adenosyl methionine and protein L-glutamic acid, whereas its two products are S-adenosylhomocysteine and protein L-glutamate methyl ester. This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-L-methionine:protein-L-glutamate O-methyltransferase. Other names in common use include methyl-accepting chemotaxis protein O-methyltransferase, S-adenosylmethionine-glutamyl methyltransferase, methyl-accepting chemotaxis protein methyltransferase II, S-adenosylmethionine:protein-carboxyl O-methyltransferase, protein methylase II, MCP methyltransferase I, MCP methyltransferase II, protein O-methyltransferase, protein(aspartate)methyltransferase, protein(carboxyl)methyltransferase, protein carboxyl-methylase, protein carboxyl-O-methyltransferase, protein carboxylmethyltransferase II, protein carboxymethylase, protein carboxymethyltransferase, and protein methyltransferase II. This enzyme participates in bacterial chemotaxisl. CheR proteins are part of the chemotaxis signaling mechanism which methylates the chemotaxis receptor at specific glutamate residues. Methyl transfer from the ubiquitous S-adenosyl-L-methionine (AdoMet/SAM) to either nitrogen, oxygen or carbon atoms is frequently employed in diverse organisms ranging from bacteria to plants and mammals.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.