The short version of Heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-10-17. Anything still debated is marked as such rather than presented as settled.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
89Sr is the active ingredient in Metastron, a radiopharmaceutical used for bone pain secondary to metastatic bone cancer. The strontium is processed like calcium by the body, preferentially incorporating it into bone at sites of increased osteogenesis. This localization focuses the radiation exposure on the cancerous lesion. 90Sr has been used as a power source for radioisotope thermoelectric generators (RTGs). 90Sr produces approximately 0.93 watts of heat per gram (it is lower for the form of 90Sr used in RTGs, which is strontium fluoride). However, 90Sr has one third the lifetime and a lower density than 238Pu, another RTG fuel. The main advantage of 90Sr is that it is significantly cheaper than 238Pu and is found in nuclear waste. The latter must be prepared by irradiating 237Np with neutrons then separating the modest amounts of 238Pu. The principal disadvantage of 90Sr is the high energy beta particles produce Bremsstrahlung as they encounter nuclei of other nearby heavy atoms such as adjacent strontium. This is mostly in the range of X-rays. Thus strong beta emitters also emit significant secondary X-rays in most cases. This requires significant shielding measures which complicates the design of RTGs using 90Sr. The Soviet Union deployed nearly 1000 of these RTGs on its northern coast as a power source for lighthouses and meteorology stations.
=== Development === The project started with producer Mace Neufeld, and was intended as a prestige thriller headlined by James Caan but that version stalled due to difficulties with the script. Neufeld later partnered with Moshe Diamant to pitch it, under the title Heart of Stone, to football player and aspiring actor Brian Bosworth. Diamant's Epic Productions had formed a joint venture with Michael Douglas and Rick Bieber's Stonebridge Entertainment called the Stone Group and the Douglas connection was an added incentive to Bosworth. Joining the other executive producers was Gary Wichard, Bosworth's personal manager who had spearheaded his transition to movies. Producer duties were entrusted to Yoram Ben Ami, CEO of Triumph Releasing, a Columbia Pictures subsidiary that usually dealt with Diamant's product. During pre-production, the screenplay was attributed to Walter Doninger and Howard Cushnir (the latter is absent from the final credits). It was retooled for Bosworth, who consulted with the writers over about one year. A late pre-production report claimed that the story was to be set in the Midwest. However, Ben Ami indicated that the Deep South region had been chosen because it was in the script, and some of the eventual locations had been in talks to host since at least summer 1989.
The substrates of this enzyme are mevalonic acid, coenzyme A, and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA), reduced NADH, and two protons. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (R)-mevalonate:NAD+ oxidoreductase (CoA-acylating). Other names in common use include beta-hydroxy-beta-methylglutaryl coenzyme A reductase, beta-hydroxy-beta-methylglutaryl CoA-reductase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and hydroxymethylglutaryl coenzyme A reductase.
Sources: en.wikipedia.org
Jeremy Isaacs (born 28 September 1932) author of four books; creator of The World at War, British documentary television series chronicling the events of the Second World War recipient of many British Academy Television Awards and International Emmy Awards; won the British Film Institute Fellowship in 1986, the International Emmy Directorate Award in 1987 and the BAFTA Fellowship in 1985, General Director of the Royal Opera House, Covent Garden from 1987 to 1996; was the founding chief executive of Channel 4 between 1981 and 1987. Jonathan Israel (b. 1946); historian specialising in Dutch history, the Age of Enlightenment, Spinoza's Philosophy and European Jews; Professor at Institute for Advanced Study, Princeton, New Jersey, previously Professor at University College London; has focused his attention on multi-volume history of the Age of Enlightenment, contrasting two camps; "radical Enlightenment" was founded on rationalist materialism articulated by Spinoza and in opposition was "moderate Enlightenment" which he sees as weakened by its belief in God. Naomi Jacob, (1 July 1884 – 27 August 1964), also known by the pen name Ellington Gray, was an English writer, actress, broadcaster and lesbian of Jewish origin. Her father rejected his Jewish ancestry but Naomi Jacob embraced it. Joseph Jacobs folklorist Howard Jacobson (born 1942) author; has described himself as "a Jewish Jane Austen" (in response to being described as "the English Philip Roth"), and also states, "I'm not by any means conventionally Jewish. I don't go to shul.
The various tests to find how the protein is used in epithelial repair displayed how its mechanism is primarily through cell migration and not through an increase in the amount of galectins produced and how galectin-7 specifically is a broad-wound repair factor instead of being labelled as a specialized marker for injury repair. Galectin-7 has potential to be a therapeutic target because of its connections to corneal injuries, skin wounds, kidney epithelial injury, and endometrial repair disorders, when the protein is rendered non-functional, therefore causing these injuries to worsen and become hard to treat.
== References == Arsdel, Wallace, B. Van, Michael, J Copley, and Robert, L. Olson. Quality and Stability of Frozen Foods: Time-Temperature Tolerance and its Significance. New York, NY: John Wiley & Sons, INC, 1968. "Clarence Birdseye." Encyclopedia of World Biography. Vol. 19. 2nd ed. Detroit: Gale, 2004. 25–27. Gale Virtual Reference Library. Gale. Brigham Young University – Utah. 3 November 2009. (subscription required) Copson, David. Microwave Heating. 2nd ed.. Westport, CT: The AVI Publishing Company, INC., 1975. Decareau, Robert. Microwave Foods: New Product Development. Trumbull, CT: Food & Nutrition Press, INC., 1992. Gould, Grahame. New Methods of Food Preservation. New York, NY: Chapman & Hall, 2000. Mathlouthi, Mohamed. Food Packaging and Preservation. New York, NY: Chapman & Hall, 1994.*^Robinson, Richard. Microbiology of Frozen Foods. New York, NY: Elsevier Applied Science Publishers LTD, 1985. Russell, Nicholas J., and Grahame W. Gould. Food Preservatives. 2nd ed. New York, NY: Kluwer Academic/Plenum Publishers, New York, 2003. Sun, Da-Wen. Handbook of Frozen Food Processing and Packaging. Boca Raton, Fl: Taylor & Francis Group, LLC, 2006. Tressler, Donald K., Clifford F. Evers, and Barbara, Hutchings Evers. Into the Freezer – and Out. 2nd ed. New York, NY: The AVI Publishing Company, INC., 1953. Tressler, Donald K., and Clifford F. Evers. The Freezing Preservation of Foods. 3rd ed. 1st volume. Westport, CT: The AVI Publishing Company, INC., 1957. Whelan, Elizabeth M., and Fredrick J. Stare. Panic in the Pantry: Facts and Fallacies About the Food You Buy.
Sources: en.wikipedia.org
== Lysosomal Ca2+-signalling modalities == The ER and acidic Ca2+ stores have similarities as well as key differences. Both transport Ca2+ into their lumina where it is stored, and is subsequently released in response to stimuli by opening resident Ca2+ channels. Indeed, the free [Ca2+] of each is broadly similar (~0.5-1.0 mM). However, they differ in the cohort of transporters, their luminal pH and their total volume per cell. The total amount of Ca2+ that is stored in each is a product of the volume and concentration; since the [Ca2+] is the same for each, the total amount of releasable Ca2+ is directly proportional to the organellar volume and therefore lysosomes can release only a small amount Ca2+ of when compared to the ER. This is important because the maximal Ca2+ release from lysosomes is so small that it is frequently 'invisible' in global Ca2+ recordings e.g. using cytosolic fluorescent reporters. In contrast, ER-derived Ca2+ is globally substantial and the predominant intracellular signal visible in global recordings. If lysosomal Ca2+ release is so small, how then can it affect cellular physiology? The answer is that it can exert its effects in two different signalling modalities: local and global, as shall be described. In bacterial infection, however, NAADP induction of lysosomal Ca2+ efflux and TFEB activation leads to enhanced expression of inflammatory cytokines.
=== Others === HiBiT-tag was developed by Scientists at Promega. It is an 11-amino-acid peptide tag, and it can be fused to the N- or C-terminus or internal locations of proteins. Its small size leads to a rapid knock-in of this tag with other proteins through CRISPR/Cas9 technology.
Convergent evolution—the repeated evolution of similar traits in multiple lineages which all ancestrally lack the trait—is rife in nature, as illustrated by the examples below. The ultimate cause of convergence is usually a similar evolutionary biome, as similar environments will select for similar traits in any species occupying the same ecological niche, even if those species are only distantly related. In the case of cryptic species, it can create species which are only distinguishable by analysing their genetics. Distantly related organisms often develop analogous structures by adapting to similar environments.
=== Ber–Bla === Paul Berg (1926–2023), American biochemist known for research on nucleic acids, especially recombinant DNA, 1980 Nobel Prize in Chemistry Friedrich Bergius (1884–1949), German chemist known for known for production of synthetic fuel from coal, 1931 Nobel Prize in Chemistry Helen M. Berman (born 1943), American chemist who worked on structural analysis of protein-nucleic acid complexes Marcellin Berthelot (1827–1907), French chemist, a prominent anti-vitalist who synthesized many organic compounds from inorganic substances, and developed thermochemistry Claude Louis Berthollet (1748–1822), French chemist who developed the theory of chemical equilibria Carolyn R. Bertozzi (born 1966) American chemist who studies chemical reactions compatible with living systems ("bioorthogonal chemistry"), 2022 Nobel Prize in Chemistry Guy Bertrand (born 1952) French chemist working on carbenes, nitrenes, phosphinidenes, radicals and biradicals Jöns Jakob Berzelius (1779–1848), Swedish chemist who discovered several elements Johannes Martin Bijvoet (1892–1980), Dutch chemist and crystallographer who determined the absolute configuration of sodium rubidium tartrate Leonora Bilger (1893–1975), American chemist who studied nitrogenous compounds Katherine Bitting (1869–1937), Canadian and American food chemist for the United States Department of Agriculture and the National Canners Association Joseph Black (1728–1799), British chemist known for discoveries of magnesium, latent heat, specific heat, and carbon dioxide
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.