TKPRPGP is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-05-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
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.
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 |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
=== Oxanorbornadiene cycloaddition === The oxanorbornadiene cycloaddition is a 1,3-dipolar cycloaddition followed by a retro-Diels Alder reaction to generate a triazole-linked conjugate with the elimination of a furan molecule. Preliminary work has established its usefulness in peptide labeling experiments, and it has also been used in the generation of SPECT imaging compounds. More recently, the use of an oxanorbornadiene was described in a catalyst-free room temperature "iClick" reaction, in which a model amino acid is linked to the metal moiety, in a novel approach to bioorthogonal reactions.
Most birds can fly, which distinguishes them from almost all other vertebrate classes. Flight is the primary means of locomotion for most bird species and is used for searching for food and for escaping from predators. Birds have various adaptations for flight, including a lightweight skeleton, two large flight muscles, the pectoralis (which accounts for 15% of the total mass of the bird) and the supracoracoideus, as well as a modified forelimb (wing) that serves as an aerofoil. Wing shape and size generally determine a bird's flight style and performance; many birds combine powered, flapping flight with less energy-intensive soaring flight. About 60 extant bird species are flightless, as were many extinct birds. Flightlessness often arises in birds on isolated islands, most likely due to limited resources and the absence of mammalian land predators. Flightlessness is almost exclusively correlated with gigantism due to an island's inherent condition of isolation. Although flightless, penguins use similar musculature and movements to "fly" through the water, as do some flight-capable birds such as auks, shearwaters and dippers.
Malaysia is a country in Southeast Asia. A federal constitutional monarchy, it consists of 13 states and three federal territories, separated by the South China Sea into two regions: Peninsular Malaysia on Mainland Southeast Asia and East Malaysia on the island of Borneo. Peninsular Malaysia shares land and maritime borders with Thailand, as well as maritime borders with Singapore, Vietnam, and Indonesia; East Malaysia shares land borders with Brunei and Indonesia, and maritime borders with the Philippines and Vietnam. Kuala Lumpur is the country's national capital, largest city, and the seat of the legislative branch of the federal government, while Putrajaya is the federal administrative capital, representing the seat of both the executive branch and the judicial branch of the federal government. With a population of over 34 million, it is the world's 43rd-most populous country. The country has its origins in the Malay kingdoms, which, from the 18th century on, became subject to the British Empire, along with the British Straits Settlements protectorate. During World War II, British Malaya, along with other nearby British and American colonies, was occupied by the Empire of Japan. Following three years of occupation, Malaya was briefly unified as the Malayan Union in 1946 until 1948 when it was restructured as the Federation of Malaya. The country achieved independence on 31 August 1957. On 16 September 1963, independent Malaya united with the then British crown colonies of North Borneo, Sarawak, and Singapore to become Malaysia.
Sources: en.wikipedia.org
Strigolactones (SLs) were originally discovered through studies of the germination of the parasitic weed Striga lutea. It was found that the germination of Striga species was stimulated by the presence of a compound exuded by the roots of its host plant. It was later shown that SLs that are exuded into the soil also promote the growth of symbiotic arbuscular mycorrhizal (AM) fungi. More recently, another role of SLs was identified in the inhibition of shoot branching. This discovery of the role of SLs in shoot branching led to a dramatic increase in the interest in these hormones, and it has since been shown that SLs play important roles in leaf senescence, phosphate starvation response, salt tolerance, and light signalling.
== Afferent inputs == The PVN receives afferent inputs from many brain regions and different parts of the body, by hormonal control. Among these, inputs from neurons in structures adjacent to the anterior wall of the third ventricle (the "AV3V region") carry information about the electrolyte composition of the blood, and about circulating concentrations of such hormones as angiotensin and relaxin, to regulate the magnocellular neurons. Inputs from the brainstem (the nucleus of the solitary tract) and the ventrolateral medulla carry information from the heart and stomach. Inputs from the hippocampus to the CRH neurones are important regulators of stress responses. Inputs from neuropeptide Y-containing neurons in the arcuate nucleus coordinate metabolic regulation (via TRH secretion) with regulation of energy intake. Specifically, the projections from the arcuate nucleus seem to exert their effect on appetite via MC4R-expressing oxytocinergic cells of the PVN. Inputs from suprachiasmatic nucleus about levels of lighting (circadian rhythms). Inputs from glucose sensors within the brain stimulate release of vasopressin and corticotropin-releasing hormone from parvocellular neurosecretory cells.
Some substrates (e.g., molecular oxygen) have a triplet ground state, which results that metals with half-filled orbitals have a tendency to react with such substrates (it must be said that the dioxygen molecule also has lone pairs, so it is also capable to react as a 'normal' Lewis base). If the ligands around the metal are carefully chosen, the metal can aid in (stoichiometric or catalytic) transformations of molecules or be used as a sensor.
Sources: en.wikipedia.org
=== 17 April === Russian opposition activist Vladimir Kara-Murza was sentenced to twenty-five years imprisonment for treason and discrediting the Russian military. Slovakia banned the import of grain from Ukraine, following a similar decision by Poland and Hungary on 15 April. Russian President Vladimir Putin visited military commanders in the Russian-occupied part of the Kherson Oblast and troops in Luhansk. In Luhansk he gave soldiers "copies of icons as a gift" for Russian Orthodox Easter which was 16 April. Although Kremlin spokesman Dmitry Peskov said the visit was 17 April, President Putin was heard saying Easter is "coming up". Subsequently, this was edited from the footage of the visit. While Ukrainian forces were training in Europe a Leopard 2A4 was damaged, with the turret being completely dislodged from the hull. The crew were reported as being fine. The accident was believed to be due to crew error or the age of the tank. Slovakia finished its delivery of 13 MiG-29 fighter jets to Ukraine.
=== Antidote to heparin === Protamine sulfate has been given to counteract the anticoagulant effect of heparin (1 mg per 100 units of heparin that had been given over the past 6 hours). It may be used in those who overdose on heparin or to reverse heparin's effect when it is no longer needed.
== Applications == Applications include alteration of gene expression - both as inhibitor and promoter in different cases, antigene and antisense therapeutic agent, anticancer agent, antiviral, antibacterial and antiparasitic agent, molecular tools and probes of biosensor, detection of DNA sequences, and nanotechnology. PNAs can be used to improve high-throughput 16S ribosomal RNA gene sequencing of plant and soil samples by blocking amplification of contaminant plastid and mitochondrial sequences. Cellular – Functional Antagonism/Inhibition. In 2001, Strauss and colleagues reported the design of an application for PNA oligomers in living mammalian cells. The Xist chromatin binding region was first elucidated in female mouse fibroblastic cells, and embryonic stem cells though the use of a PNA molecular antagonist. The novel PNA approach directly demonstrated function of a lncRNA. The long non-coding (lncRNA) RNA, Xist directly binds to the inactive X-chromosome. Functional PNA inhibition experiments revealed that specific repeat regions of the Xist RNA were responsible for chromatin binding, and hence could be considered domain regions of the RNA transcript. The PNA molecular antagonist was administered to living cells and functionally inhibited the association of Xist with inactive X-chromosome using the approach for studying noncoding RNA function in living cells called peptide nucleic acid (PNA) interference mapping. In the reported experiments, a single 19-bp antisense cell-permeating PNA targeted against a particular region of Xist RNA caused the disruption of the Xi.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
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.