The short version of Heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-03-26 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
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.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
== Process == The lenticule to be extracted is accurately cut to the correction prescription required by the patient using a photodisruption laser-tissue interaction. The posterior intrastromal plane is created first and the anterior plane second. To allow better separation, the two lenticule faces are cut by the laser head moving in a spiral fashion - conventionally outside in for the posterior face and respectively inside out for the anterior one. The minimum lenticule edge thickness is usually set at 15 μm, to avoid the risk of lenticule rupturing during detachment and subsequent extraction. The method of extraction was via a LASIK-type flap in ReLEx FLEx, but in SMILE a flapless technique makes a small tunnel incision in the corneal periphery, that does not (mostly) destroy Bowman's layer. One conspicuous difference between SMILE and LASIK is the size and shape of the corneal incision. In LASIK, the surgeon performs a 270-degree, 20 mm long incision, while in SMILE the so-called "side cap cut", which is the incision through which the surgeon extracts the lenticule, is usually about 4 mm long. Currently in the US the procedure is only approved for nearsightedness, but is used for hypermetropia too in other countries. After the femtosecond laser has separated the lenticule, a blunt spatula is inserted through the incision between the lenticule and the stroma and carefully rotated to ensure that the lenticule is completely detached prior to removal by forceps.
=== Video game === Chase: Cold Case Investigations - Distant Memories is a video game about two detectives of the Tokyo Metropolitan Police Department's cold case unit, Shounosuke Nanase and Koto Amekura. Cold Case Inc is an online platform that publishes interactive, document-driven unsolved case file games.
Much of the universe's water is produced as a byproduct of star formation. The formation of stars is accompanied by a strong outward wind of gas and dust. When this outflow of material eventually impacts the surrounding gas, the shock waves that are created compress and heat the gas. The water observed is quickly produced in this warm dense gas. On 22 July 2011, a report described the discovery of a gigantic cloud of water vapor containing "140 trillion times more water than all of Earth's oceans combined" around a quasar located 12 billion light years from Earth. According to the researchers, the "discovery shows that water has been prevalent in the universe for nearly its entire existence". Water has been detected in interstellar clouds within the Milky Way. Water probably exists in abundance in other galaxies, too, because its components, hydrogen, and oxygen, are among the most abundant elements in the universe. Based on models of the formation and evolution of the Solar System and that of other star systems, most other planetary systems are likely to have similar ingredients.
INS: The insulin gene (INS) on chromosome 11p15 is one of the earliest identified non-HLA genes linked to T1D. A variable number tandem repeat (VNTR) polymorphism in the promoter region of the insulin gene affects its thymic expression, with certain alleles reducing the ability to develop immune tolerance to insulin, a key autoantigen in T1D. PTPN22: This gene encodes a protein tyrosine phosphatase involved in T-cell receptor signaling. A common single-nucleotide polymorphism (SNP), R620W, in the PTPN22 gene is associated with an increased risk of T1D and other autoimmune diseases, suggesting its role in modulating immune responses. IL2RA: The interleukin-2 receptor alpha (IL2RA) gene, located on chromosome 10p15, plays a crucial role in regulating immune tolerance and T-cell activation. Variants in IL2RA affect the susceptibility to T1D by altering the function of regulatory T-cells, which help maintain immune homeostasis. CTLA4: The cytotoxic T-lymphocyte-associated protein 4 (CTLA4) gene is another immune-related gene associated with T1D. CTLA4 acts as a negative regulator of T-cell activation, and certain variants are linked to impaired immune regulation and a higher risk of autoimmunity. T1D is considered a polygenic disease, meaning that multiple genes contribute to its development. While individual genes confer varying degrees of risk, it is the combination of several genetic factors, along with environmental triggers, that ultimately leads to disease onset.
=== Other organs === GnRH is found in organs outside of the hypothalamus and pituitary, and its role in other life processes is poorly understood. For instance, there is likely to be a role for GnRH1 in the placenta and in the gonads. GnRH and GnRH receptors are also found in cancers of the breast, ovary, prostate, and endometrium.
Sources: en.wikipedia.org
== History == Volufralin was originated by Uppsala University in Sweden and is under development by Dicot Pharma. As of July 2026, it is in phase 2 clinical trials for erectile dysfunction and the preclinical research stage of development for premature ejaculation. The mechanism of action of the drug of indirect melanocortin MC4 receptor potentiation was not initially disclosed, but was announced by its developer in December 2025. The exact chemical structure of volufralin was not initially disclosed, aside from it being related to the libiguins. However, in July 2026, the generic name of volufralin and its structure were published.
However, the original cold noodle dish was not soft enough, and was a little hard to chew. After the use of softer noodles, grilled cold noodles was gradually accepted by people all around China. However, grilled cold noodles are still known for their chewiness. The chewy texture comes from gluten.
Studies of food processing impact on public health and other outcomes, such as affordability, energy efficiency, food safety and sustainability benefit from the use of FPL. Several food ingredients, which have different FPL, are often used in food products. The highest FPL used to obtain ingredients for intermittent processing of formulated foods and the FPL of final processing, whichever is the highest, indicates the FPL of the final food. Final food products may be formulated using ingredients from several FPL which, when including ingredients or processing at FPL 3 and 4, are assigned to the highest FPL 4.
=== Reverse electron flow === Reverse electron flow is the transfer of electrons through the electron transport chain through the reverse redox reactions. Usually requiring a significant amount of energy to be used, this can reduce the oxidized forms of electron donors. For example, NAD+ can be reduced to NADH by Complex I. There are several factors that have been shown to induce reverse electron flow. However, more work needs to be done to confirm this. One example is blockage of ATP synthase, resulting in a build-up of protons and therefore a higher proton-motive force, inducing reverse electron flow.
Following the release and favorable reviews of Last Days Here, Liebling and Pentagram experienced a significant resurgence in popularity. The documentary won multiple awards, including the Grand Jury Prize at the Independent Film Festival of Boston and Best Music Documentary at the International Documentary Film Festival Amsterdam. This renewed attention revitalized Pentagram's career, leading to international tours. Releasing a new album around the same time the documentary was published accelerated the band's resurgence. Liebling, alongside longtime collaborator Victor Griffin, returned to the studio for Last Rites, which was released in April 2011. This marked Griffin's first studio work with Pentagram in over 15 years. At the time, Liebling noted that he had written the music and lyrics for about half of the band's earlier albums, "while 30–40% were collaborations with musicians, typically guitar players". Regarding his songwriting approach for the "Last Rites", he said: "I just write the lyrics nowadays. I ran out of music. I wrote 450 songs in 30 years." In 2011, Metal Blade Records announced Pentagram's return to live performances, which included an appearance at South by Southwest and a European tour that began at the Roadburn Festival in the Netherlands. Liebling embarked on extensive touring across North America and Europe with Pentagram in the following years. However, the band continued to experience frequent lineup changes. Pentagram maintained its momentum with the release of the album Curious Volume on August 21, 2015.
Sources: en.wikipedia.org
==== Less frequent ==== Hb H (β4) Hb Barts (γ4) Hb O (α2βO2) Hb Bassett Hb Kansas Hb D-Punjab Hb O-Arab Hb G-Philadelphia Hb Hasharon Hb Kirklareli Hb Lepore Hb M Hb Hope Hb Pisa Hb J Hb N-Baltimore Hemoglobin Chesapeake Hemoglobin Louisville Hemoglobin Vanvitelli
=== Solvents === CV can be conducted using a variety of solutions. Solvent choice for cyclic voltammetry takes into account several requirements. The solvent must dissolve the analyte and high concentrations of the supporting electrolyte. It must also be stable in the potential window of the experiment with respect to the working electrode. It must not react with either the analyte or the supporting electrolyte. It must be pure to prevent interference.
While the fair was profitable, it nevertheless left Knoxville in debt, and failed to spark the redevelopment boom Testerman, Tyree, and the fair's promoters had envisioned. Furthermore, on the day after the fair closed, the FDIC raided all of Butcher's banks, leading to the collapse of his banking empire, and threatening the city's financial stability. Testerman replaced an embattled Tyree as mayor in 1983, and attempted to reinvigorate interest in his downtown redevelopment plans.
Sexual medicine is concerned with diagnosing, assessing and treating all disorders related to sexuality. Sports medicine deals with the treatment and prevention and rehabilitation of sports/exercise injuries such as muscle spasms, muscle tears, injuries to ligaments (ligament tears or ruptures) and their repair in athletes, amateur and professional. Therapeutics is the field, more commonly referenced in earlier periods of history, of the various remedies that can be used to treat disease and promote health. Travel medicine or emporiatrics deals with health problems of international travelers or travelers across highly different environments. Tropical medicine deals with the prevention and treatment of tropical diseases. It is studied separately in temperate climates where those diseases are quite unfamiliar to medical practitioners and their local clinical needs. Urgent care focuses on delivery of unscheduled, walk-in care outside of the hospital emergency department for injuries and illnesses that are not severe enough to require care in an emergency department. In some jurisdictions this function is combined with the emergency department. Veterinary medicine; veterinarians apply similar techniques as physicians to the care of non-human animals. Wilderness medicine entails the practice of medicine in the wild, where conventional medical facilities may not be available.
Sources: en.wikipedia.org
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.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.