This is a working overview of Heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-21 and is reviewed periodically as new material appears.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
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 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.
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.
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.
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.
2023, Overseas Fellow of the Australian Academy of Technological Sciences and Engineering (FTSE) 2019, Othmer Gold Medal, Science History Institute and others 2018, honorary Doctorate, Utrecht University 2017, Catalyst Award, Science Club for Girls 2015, Heinz Award, Heinz Family Foundation, in the Technology, the Economy and Employment category "for her seminal work in tissue engineering and disease detection, including the cultivation of functional liver cells outside of the human body, and for her passion in promoting the advancement of women in the STEM fields." 2014, Lemelson-MIT Prize, Massachusetts Institute of Technology "for her dedication to the next generation of scientists, and groundbreaking inventions to improve human health and patient care on a global scale." 2011, BEAM (Brown Engineering Alumni Medal) Award, Brown University School of Engineering 2008, Howard Hughes Medical Institute investigator 1999, Packard Fellowship, David and Lucile Packard Foundation
== Endurance sports == The use of performance-enhancing drugs in sport has become an increasing problem across a wide range of sports. It is defined as any substance or drug that, when taken, gives an athlete an unfair advantage relative to a "clean" athlete. The banning of these drugs promotes a level playing field and equality among athletes. The use of 'the suit' in swimming, which gives athletes an advantage in the way of hydrodynamics, has been banned from international competition due to the unfair advantage it delivered. The drugs taken by athletes differ widely based on the performance needs of the sport. Erythropoietin (EPO) is largely taken by endurance athletes who seek a higher level of red blood cells, which leads to more oxygenated blood, and a higher VO2 max. An athlete's VO2 max is highly correlated with success within endurance sports such as swimming, long-distance running, cycling, rowing, and cross-country skiing. EPO has recently become prevalent amongst endurance athletes due to its potency and low degree of detectability when compared to other methods of doping such as blood transfusion. While EPO is believed to have been widely used by athletes in the 1990s, there was not a way to directly test for the drug until 2002 as there was no specific screening process to test athletes. Athletes at the Olympic Games are tested for EPO through blood and urine tests. Stringent guidelines and regulations can lessen the danger of doping that has existed within some endurance sports. A notable case being TJ Dillashaw.
=== Past exposure to psychiatric medications theory === The past exposure theory suggests that exposure to psychiatric medication alters neural synapses, introducing an imbalance that was not previously present. Discontinuation of the drug is expected to result in symptoms of psychiatric illness which resolve once the drug is restarted. This theory suggests that while it may appear that the medication is working, it is only treating a disorder caused by the medication itself. New exposure to psychiatric medication may lead to heightened sensitivity to the effects of drugs such as alcohol, which has a deteriorating effect on the patient.
Sources: en.wikipedia.org
A year later, a further discovery was made at Lindow Moss, just 250 m (820 ft) southwest of the Lindow Woman. On 1 August 1984, Andy Mould, who had been involved in the discovery of Lindow Woman, took what he thought was a piece of wood off the elevator of the peat-shredding machine. He threw the object at Eddie Slack, his workmate. When it hit the ground, peat fell off the object and revealed it to be a human foot. The police were called, and the foot was taken away for examination. At the same time Rachel Pugh, a trainee journalist for The Wilmslow World, was tipped off about the discovery. At the urging of her editor, she cycled out to the site of the discovery and persuaded the two men to show her where the foot had been excavated. Recognising the possible historical significance of the find, she told the diggers to stop work at once, and alerted Rick Turner, the Cheshire County Archaeologist, who subsequently succeeded in finding the rest of the body, which later became known as Lindow Man. Some skin had been exposed and had started to decay, so to prevent further deterioration of the body, it was re-covered with peat. The complete excavation of the block containing the remains was performed on 6 August. Until it could be dated, it was moved to the Macclesfield District General Hospital for storage. As the body of Malika Reyn-Bardt had still not been found, it was initially thought possible the body might be hers, until it was determined to be male, and radiocarbon dated.
Furthermore, harkening back to Urey's original hypothesis of a "post-impact" reducing atmosphere, a recent atmospheric modeling study has shown that an iron-rich impactor with a minimum mass around 4×1020 – 5×1021 kg would be enough to transiently reduce the entire prebiotic atmosphere, resulting in a Miller–Urey-esque H2-, CH4-, and NH3-dominated atmosphere that persists for millions of years. Previous work has estimated from the lunar cratering record and composition of Earth's mantle that between four and seven such impactors reached the Hadean Earth.
==== Inverted burial ==== For humans, maintaining an upside-down position, with the head vertically below the feet, is highly uncomfortable for any extended period of time, and consequently burial in that attitude (as opposed to attitudes of rest or watchfulness, as above) is highly unusual and generally symbolic. Occasionally suicides and assassins were buried upside down, as a post-mortem punishment and (as with burial at cross-roads) to inhibit the activities of the resulting undead. In Gulliver's Travels, the Lilliputians buried their dead upside down:
Sources: en.wikipedia.org
4-Fluoro-7-nitrobenzofurazan (NBD-F) is a fluorogenic, amine labeling dye that is not fluorescent itself, but covalently reacts with secondary or primary amines to form a fluorescently labeled product. It and other fluorogenic benzofurans (i.e. NBD-Cl) are used for derivitization in HPLC applications. After the fluorogenic reaction, it can be detected with an excitation wavelength of 470 nm (blue) and an emission wavelength of 530 nm (green), enabling an HPLC limit of detection of 10 fmol.
carbohydrate Any of a class of organic compounds having the generic chemical formula (CH2O)n, and one of several major classes of biomolecules found universally in biological systems. Carbohydrates include individual monosaccharides as well as larger polymeric oligosaccharides and polysaccharides, in which multiple monosaccharide monomers are joined by glycosidic bonds. Abundant and ubiquitous, these compounds are involved in numerous essential biochemical processes and pathways; they are widely used as an energy source for cellular metabolism, as a form of energy storage, as signaling molecules, and as biomarkers to label or modify the activity of other molecules. Carbohydrates are often colloquially described as "sugars"; the prefix glyco- indicates a compound or process containing or involving carbohydrates, and the suffix -ose usually signifies that a compound is a carbohydrate or a derivative.
Neomorphic mutations are a part of the gain-of-function mutations and are characterized by the control of new protein product synthesis. The newly synthesized gene normally contains a novel gene expression or molecular function. The result of the neomorphic mutation is the gene where the mutation occurs has a complete change in function. A reversion (or back mutation) is a point mutation that restores the original sequence and hence the original phenotype.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.