This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-01-19. Anything still debated is marked as such rather than presented as settled.
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.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For lyophilized powder, long term |
| Common analytical method | Reverse-phase HPLC | Usually paired with mass spectrometry |
| Typical reported purity | At or above 95 percent by area | Research-grade material |
| Aqueous solubility | High | Solutions used in laboratory assays |
| Moisture sensitivity | Hydrolyzes in solution | Aseptic handling reduces degradation |
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
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.
=== Serotonin–norepinephrine reuptake inhibitors === Serotonin–norepinephrine reuptake inhibitor (SNRIs) include venlafaxine and duloxetine drugs. Venlafaxine, in extended release form, and duloxetine, are indicated for the treatment of GAD. SNRIs are as effective as SSRIs in the treatment of anxiety disorders.
Alternative Splicing: In this mechanism, alternative splicing of the RAGE gene produces a variant that lacks the membrane-anchoring and cytoplasmic segments, creating a soluble form of the receptor Proteolytic Cleavage: Alternatively, sRAGE can be produced by proteolytic cleavage of the membrane-bound receptor. This involves enzymes, such as matrix metalloproteinases (MMPs) and ADAM10, cleaving the extracellular portion of mRAGE, which is then released into the circulation.
== Recalls == In 2018–2019, Teva Pharmaceuticals USA recalled antihypertensive tablets containing valsartan and losartan due to the detection beyond acceptable limit of N-nitrosodiethylamine (NDEA) and N-Nitroso-N-methyl-4-aminobutyric acid (NMBA), respectively, which are probable human carcinogens.
Sources: en.wikipedia.org
== Effects == In humans there are local effects which appear within minutes: edema, erythema and numbness, following by systemic effects which include general weakness, sweating, pallor, fluctuations in the level of consciousness, vomiting, watery non-bloody diarrhea, high blood pressure, liver damage, hemorrhage, dyspnea, hypoxia, hypercapnia and disorders of cardiac activity. The reports of cardiac disorders describe a prolonged P-R interval and changes in the S-T segment. The cardiac disorders may be due to either direct effects of the venom to the heart or to hypoxia caused by respiratory disturbances.
The manufacture of antidotes called mithridate or theriac (English "treacle") continued into the nineteenth century. Ephraim Chambers, in his 1728 Cyclopaedia, says "Mithridate is one of the capital Medicines in the Apothecaries Shops, being composed of a vast Number of Drugs, as Opium, Myrrh, Agaric, Saffron, Ginger, Cinnamon, Spikenard, Frankincense, Castor, Pepper, Gentian, &c. It is accounted a Cordial, Opiate, Sudorific, and Alexipharmic". Petrus Andreas Matthiolus considered it more effectual against poisons than Venice treacle, and easier to make. Late versions of the antidote incorporated dried blood or the dried flesh of lizards or vipers or Malabathrum.
== Inhibition == The main inhibitor of tissue plasminogen activator and urokinase is plasminogen activator inhibitor-1 (PAI-1). Plasminogen activator inhibitor-1 is a serine protease, synthesized by endothelial cells, that specifically inhibits tissue plasminogen activator (tPA) and urokinase (uPA). Tissue plasminogen activator and urokinase are the activators of plasminogen and result in the breakdown of blood clots (fibrinolysis). PAI-1 levels have also been studied in patients and how they influence certain diseases. Elevated serum levels of PAI-1 have been found in obese individuals. Elevated levels of PAI-1 also seem to increase the risk of atherothrombotic events and may also promote vascular disease. Plasminogen activator inhibitor-2 (PAI-2) is a serine protease that inactivates tPA and uPA. PAI-2 is produced by the placenta and only found in high quantities in the blood during pregnancy.
Sources: en.wikipedia.org
microsatellite Also short tandem repeat (STR) or simple sequence repeat (SSR). A type of satellite DNA consisting of a relatively short sequence of tandem repeats, in which certain motifs (ranging in length from one to six or more bases) are repeated, typically 5–50 times. Microsatellites are widespread throughout most organisms' genomes and tend to have higher mutation rates than other regions. They are classified as variable number tandem repeat (VNTR) DNA, along with longer minisatellites.
The neighbouring powers took advantage of the situation: the Habsburg Monarchy annexed the northwestern part of Moldavia, or Bukovina, in 1775, and the Russian Empire seized the eastern half of Moldavia, or Bessarabia, in 1812. A census revealed that the Romanians were more numerous than any other ethnic group in Transylvania in 1733, but legislation continued to use contemptuous adjectives (such as "tolerated" and "admitted") when referring to them. The Uniate bishop, Inocențiu Micu-Klein, who demanded recognition of the Romanians as the fourth privileged nation, was forced into exile. Uniate and Orthodox clerics and laymen jointly signed a plea for the Transylvanian Romanians' emancipation in 1791, but the monarch and the local authorities refused to grant their requests.
Targeted at the Southern states, the Agricultural College Act of 1890 required states to establish land-grant universities for African Americans if they were excluded from the state's existing land-grant institutions. The Civil Rights Act of 1964, the Higher Education Act of 1965, and the Education Amendments of 1972, made public universities even more accessible for women, minorities, and lower-income applicants. A number of U.S. public universities began as teacher training institutions, often named normal schools or teachers colleges, and eventually expanded into comprehensive universities. Examples include the University of California, Los Angeles; Arizona State University; the University of Wisconsin–Milwaukee; and Missouri State University. There are also public tribal colleges and universities operated by Native Americans, and some colleges where a municipal government is an owner or part of governance such as the City University of New York and Quincy College. Federally chartered public universities include the United States service academies that are administered by the United States Department of Defense and the Haskell Indian Nations University, which the Bureau of Indian Affairs governs. The University of the District of Columbia is the public university in Washington, D.C., overseen by the Government of the District of Columbia under authority devolved from Congress under District of Columbia home rule. Private universities in the District of Columbia also hold federal charters but are not public.
Sources: en.wikipedia.org
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.
Lyophilized powder is usually kept frozen and protected from moisture. Solutions are less stable and are often used promptly or divided into aliquots to avoid repeated freeze-thaw cycles. Exact shelf-life values depend on purity and handling.
No. A purity figure derived from chromatographic area does not prove the amino acid sequence. Identity requires an orthogonal method such as mass spectrometry or sequencing. Truncated or isomerized peptides can co-elute with the target compound.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.