If you have been reading about Tuftsin 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 2025-12-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
By the 1801 Treaty of Lunéville, the last Este Duke was compensated with the Breisgau region of the former Further Austrian territories in southwestern Germany, and died in 1803. Following his death, the claims to the no longer existing ducal crown of Modena were inherited by his son-in-law, the Habsburg-Lorraine Archduke Ferdinand of Austria, an uncle of Emperor Francis II.
=== Insects as a novel protein source for pet food === A challenge that is presented when feeding companion animals with food intolerance or sensitivities is finding protein sources that will not irritate their gastrointestinal tracts. Animal protein is a major cause of gastrointestinal problems, and insect protein may be an alternative source for these pets. Insects have the potential to be used as a novel protein in diets for sensitive animals. A novel protein is a protein source to which the animal has not previously been exposed. There are some risks to using novel protein sources, such as contaminants, antinutritional factors (ANFs), and allergens which are not well known. When referring specifically to dog and cat nutrition, the use of alternative protein sources must be able to deliver the ten essential amino acids (EAA) that are not synthesized from the body (including Arg, His, Ile, Leu, Lys, Met, Phe, Thr, Trp and Val). One additional amino acid which is specific to cats who are obligate carnivores by nature is taurine. This requirement is based on the low enzymatic action of cysteine dioxygenase and cysteine sulphinic acid decarboxylase within feline metabolism, where the competing pathway of pyruvate for an energy source overrides taurine synthesis. McCuster et al. created a study to identify amino acid composition of different insects, specifically addressing the presence of taurine in comparison to the National Research Council's (NRC) minimal requirements (MR) for the dog and cat.
Movat's stain is a pentachrome stain originally developed by Henry Zoltan Movat (1923–1995), a Hungarian-Canadian Pathologist in Toronto in 1955 to highlight the various constituents of connective tissue, especially cardiovascular tissue, by five colors in a single stained slide. In 1972, H. K. Russell, Jr. modified the technique so as to reduce the time for staining and to increase the consistency and reliability of the staining, creating the Russell–Movat stain.
==== Metal-free organic cavity modifiers ==== Most examples of MOF-based catalysis make use of metal ions or atoms as active sites. Among the few exceptions are two nickel- and two copper-containing MOFs synthesized by Rosseinsky and co-workers. These compounds employ amino acids (L- or D-aspartate) together with dipyridyls as struts. The coordination chemistry is such that the amine group of the aspartate cannot be protonated by added HCl, but one of the aspartate carboxylates can. Thus, the framework-incorporated amino acid can exist in a form that is not accessible for the free amino acid. While the nickel-based compounds are marginally porous, on account of tiny channel dimensions, the copper versions are clearly porous. The Rosseinsky group showed that the carboxylic acids behave as Brønsted acidic catalysts, facilitating (in the copper cases) the ring-opening methanolysis of a small, cavity-accessible epoxide at up to 65% yield. Superior homogeneous catalysts exist however. Kitagawa and co-workers have reported the synthesis of a catalytic MOF having the formula [Cd(4-btapa)2(NO3)2]. The MOF is three-dimensional, consisting of an identical catenated pair of networks, yet still featuring pores of molecular dimensions. The nodes consist of single cadmium ions, octahedrally ligated by pyridyl nitrogens. From a catalysis standpoint, however, the most interesting feature of this material is the presence of guest-accessible amide functionalities. The amides are capable of base-catalyzing the Knoevenagel condensation of benzaldehyde with malononitrile.
Sources: en.wikipedia.org
=== Laboratory applications === In the laboratory, EDTA is widely used for scavenging metal ions: In biochemistry and molecular biology, ion depletion is commonly used to deactivate metal-dependent enzymes, either as an assay for their reactivity or to suppress damage to DNA, proteins, and polysaccharides. EDTA also acts as a selective inhibitor against dNTP hydrolyzing enzymes (Taq polymerase, dUTPase, MutT), liver arginase and horseradish peroxidase independently of metal ion chelation. These findings urge the rethinking of the utilisation of EDTA as a biochemically inactive metal ion scavenger in enzymatic experiments. In analytical chemistry, EDTA is used in complexometric titrations and analysis of water hardness or as a masking agent to sequester metal ions that would interfere with the analyses. EDTA finds many specialised uses in the biomedical labs, such as in veterinary ophthalmology as an anticollagenase to prevent the worsening of corneal ulcers in animals. In tissue culture, EDTA is used as a chelating agent that binds to calcium and prevents joining of cadherins between cells, preventing clumping of cells grown in liquid suspension, or detaching adherent cells for passaging. In histopathology, EDTA can be used as a decalcifying agent making it possible to cut sections using a microtome once the tissue sample is demineralised. EDTA is also known to inhibit a range of metallopeptidases, the method of inhibition occurs via the chelation of the metal ion required for catalytic activity.
From amphibians onward, bone management is biodynamic, with bone functioning as internal calcium reservoir under the control of osteoclasts via the combined action of parathyroid hormone and 1α,25-dihydroxyvitamin D3.
On December 20, 1989, the US invaded Panama with 25,000 American troops in Operation Just Cause, to depose and arrest the Panamanian head of government, Manuel Noriega. Noriega had been providing military assistance to Contra groups in Nicaragua at the request of the US, which in turn paid him and tolerated his drug trafficking activities, known since the 1960s. Relations with the US deteriorated in the mid-1980s, and his dealings with the US government were exposed in the US news media. The killing of a US soldier in Panama was the final act leading to the invasion. Noriega surrendered to US soldiers on January 3, 1990. He was indicted by the DEA and sentenced by a US court to 45 years in prison for racketeering, drug smuggling, and money laundering. The UN General Assembly resolved that the invasion was a "flagrant violation of international law." Ecuador, located between the world's two largest cocaine-producing countries, Colombia and Peru, has long been a major drug transit point. From 1999, the Manta air base was the US military's most prominent South American presence, originating some 100 drug surveillance flights monthly. In 2009, citing unwanted internal influence by the CIA, Ecuador declined to renew the base's lease, ending official US military presence. Since 2018, drug activity and anti-drug efforts in Ecuador have dramatically intensified. In 2023, the US-Ecuador Defense Bilateral Working Group was formed to address the Ecuadorian situation, and a memorandum of agreement to help strengthen the Ecuadorian military was signed.
Sources: en.wikipedia.org
=== Approaches to improve thermostability of proteins === Protein engineering can be used to enhance the thermostability of proteins. A number of site-directed and random mutagenesis techniques, in addition to directed evolution, have been used to increase the thermostability of target proteins. Comparative methods have been used to increase the stability of mesophilic proteins based on comparison to thermophilic homologs. Additionally, analysis of the protein unfolding by molecular dynamics can be used to understand the process of unfolding and then design stabilizing mutations. Rational protein engineering for increasing protein thermostability includes mutations which truncate loops, increase salt bridges or hydrogen bonds, introduced disulfide bonds. In addition, ligand binding can increase the stability of the protein, particularly when purified. There are various different forces that allow for the thermostability of a particular protein. These forces include hydrophobic interactions, electrostatic interactions, and the presence of disulfide bonds. The overall amount of hydrophobicity present in a particular protein is responsible for its thermostability. Another type of force that is responsible for thermostability of a protein is the electrostatic interactions between molecules. These interactions include salt bridges and hydrogen bonds. Salt bridges are unaffected by high temperatures, therefore, are necessary for protein and enzyme stability. A third force used to increase thermostability in proteins and enzymes is the presence of disulfide bonds.
=== Analytical methods === Several relatively simple chemical tests—commercially available as reagent testing kits—can be used to assess the presence of psilocybin in extracts prepared from mushrooms. The drug produces a yellow color in the Marquis test and a green color in the Mandelin reagent. Neither of these tests is specific for psilocybin; for example, the Marquis test will react with many classes of controlled drugs, such as those containing primary amino groups and unsubstituted benzene rings, including amphetamine and methamphetamine. Ehrlich's reagent and DMACA reagent are used as chemical sprays to detect the drug after thin layer chromatography. Many modern techniques of analytical chemistry have been used to quantify psilocybin levels in mushroom samples. Although the earliest methods commonly used gas chromatography, the high temperature required to vaporize the psilocybin sample before analysis causes it to spontaneously lose its phosphoryl group and become psilocin, making it difficult to chemically discriminate between the two drugs. In forensic toxicology, techniques involving gas chromatography coupled to mass spectrometry (GC–MS) are the most widely used due to their high sensitivity and ability to separate compounds in complex biological mixtures. These techniques include ion mobility spectrometry, capillary zone electrophoresis, ultraviolet spectroscopy, and infrared spectroscopy. High-performance liquid chromatography (HPLC) is used with ultraviolet, fluorescence, electrochemical, and electrospray mass spectrometric detection methods.
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=== Oxidation === Plasma processing, corona treatment, and flame treatment can all be classified as surface oxidation mechanisms. These methods all involve cleavage of polymer chains in the material and the incorporation of carbonyl, and hydroxyl functional groups. The incorporation of oxygen into the surface creates a higher surface energy allowing the substrate to be coated.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
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.