Everything below concerns tuftsin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
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.
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.
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.
=== Chemical flocculant === Potassium alum has been used since remote antiquity for purification of turbid liquids. It is still widely used in the purification of water for drinking and industrial processes water, treatment of effluents and post-storm treatment of lakes to precipitate contaminants. Between 30 and 40 ppm of alum for household wastewater, often more for industrial wastewater, is added to the water so that the negatively charged colloidal particles clump together into "flocs", which then float to the top of the liquid, settle to the bottom of the liquid, or can be more easily filtered from the liquid, prior to further filtration and disinfection of the water. Like other similar salts, it works by neutralizing the electrical double layer surrounding very fine suspended particles, allowing them to join into flocs. The same principle is exploited when using alum to increase the viscosity of a ceramic glaze suspension; this makes the glaze more readily adherent and slows its rate of sedimentation.
Ribosomal RNA (rRNA) is the catalytic component of the ribosomes. The rRNA is the component of the ribosome that hosts translation. Eukaryotic ribosomes contain four different rRNA molecules: 18S, 5.8S, 28S and 5S rRNA. Three of the rRNA molecules are synthesized in the nucleolus, and one is synthesized elsewhere. In the cytoplasm, ribosomal RNA and protein combine to form a nucleoprotein called a ribosome. The ribosome binds mRNA and carries out protein synthesis. Several ribosomes may be attached to a single mRNA at any time. Nearly all the RNA found in a typical eukaryotic cell is rRNA. Transfer-messenger RNA (tmRNA) is found in many bacteria and plastids. It tags proteins encoded by mRNAs that lack stop codons for degradation and prevents the ribosome from stalling.
Antithrombin is a serpin (serine protease inhibitor) and is thus similar in structure to most other plasma protease inhibitors, such as alpha 1-antichymotrypsin, alpha 2-antiplasmin and Heparin cofactor II. The physiological target proteases of antithrombin are those of the contact activation pathway (formerly known as the intrinsic pathway), namely the activated forms of Factor X (Xa), Factor IX (IXa), Factor XI (XIa), Factor XII (XIIa) and, to a greater extent, Factor II (thrombin) (IIa), and also the activated form of Factor VII (VIIa) from the tissue factor pathway (formerly known as the extrinsic pathway). The inhibitor also inactivates kallikrein and plasmin , also involved in blood coagulation. However it inactivates certain other serine proteases that are not involved in coagulation such as trypsin and the C1s subunit of the enzyme C1 involved in the classical complement pathway. Protease inactivation results as a consequence of trapping the protease in an equimolar complex with antithrombin in which the active site of the protease enzyme is inaccessible to its usual substrate. The formation of an antithrombin-protease complex involves an interaction between the protease and a specific reactive peptide bond within antithrombin. In human antithrombin this bond is between arginine (arg) 393 and serine (ser) 394 (see Figure 2 and Figure 3). It is thought that protease enzymes become trapped in inactive antithrombin-protease complexes as a consequence of their attack on the reactive bond.
== Geographic distribution == TEV appears to be a virus that evolved in the New World. It has been reported in Canada, the United States (including Hawaii), Mexico and Puerto Rico in North America and in Venezuela in South America.
Neuromodulation, whether electrical or magnetic, employs the body's natural biological response by stimulating nerve cell activity that can influence populations of nerves by releasing transmitters, such as dopamine, or other chemical messengers such as the peptide Substance P, that can modulate the excitability and firing patterns of neural circuits. There may also be more direct electrophysiological effects on neural membranes as the mechanism of action of electrical interaction with neural elements. The end effect is a "normalization" of a neural network function from its perturbed state. Presumed mechanisms of action for neurostimulation include depolarizing blockade, stochastic normalization of neural firing, axonal blockade, reduction of neural firing keratosis, and suppression of neural network oscillations. A recent review (2024) has identified relevant etiological hypotheses of non-invasive neuromodulation in different techniques. Data analysis revealed that mitochondrial activity seems to play a central role in different techniques. Analysis of the mother-fetus neurocognitive model provided insights into the conditions of natural neuromodulation of the fetal nervous system during pregnancy.
Sources: en.wikipedia.org
The Arab Higher Committee (Arabic: اللجنة العربية العليا, romanized: al-Lajnah al-ʻArabīyah al-ʻUlyā) or the Higher National Committee was the central political organ of Palestinians in Mandatory Palestine. It was established on 25 April 1936, on the initiative of Haj Amin al-Husayni, the Grand Mufti of Jerusalem, and comprised the leaders of Palestinian Arab clans and political parties under the mufti's chairmanship. The committee was outlawed by the British Mandatory administration in September 1937 after the assassination of a British official. A committee of the same name was reconstituted by the Arab League in 1945, but went to abeyance after it proved ineffective during the 1948 Arab–Israeli War. It was sidestepped by Egypt and the Arab League with the formation of the All-Palestine Government in 1948 and both were banned by Jordan.
== Definitions == The words diaphoresis and hidrosis can both mean either perspiration (in which sense they are synonymous with sweating) or excessive perspiration (in which sense they can be either synonymous with hyperhidrosis or differentiable from it only by clinical criteria involved in narrow specialist senses of the words). Hypohidrosis is decreased sweating from whatever cause. Hyperhidrosis is excessive sweating, usually secondary to an underlying condition (in which case it is called secondary hyperhidrosis) and usually involving the body as a whole (in which case it is called generalized hyperhidrosis). Focal hyperhidrosis is increased or excessive sweating in certain regions such as the underarm, palms, soles, face, or groin. Hidromeiosis is a reduction in sweating that is due to blockages of sweat glands in humid conditions. A substance or medicine that causes perspiration is a sudorific or sudatory.
Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is usually injected by unique fangs during a bite, though some species are also able to spit venom. The venom glands that secrete zootoxins are a modification of the parotid salivary glands found in other vertebrates and are usually located on each side of the head, below and behind the eye, and enclosed in a muscular sheath. The venom is stored in large glands called alveoli before being conveyed by a duct to the base of channeled or tubular fangs through which it is ejected. Venom contains more than 20 different compounds, which are mostly proteins and polypeptides. The complex mixture of proteins, enzymes, and various other substances has toxic and lethal properties. Venom serves to immobilize prey. Enzymes in venom play an important role in the digestion of prey, and various other substances are responsible for important but non-lethal biological effects. Some of the proteins in snake venom have very specific effects on various biological functions, including blood coagulation, blood pressure regulation, and transmission of nerve or muscle impulses. These venoms have been studied and developed for use as pharmacological or diagnostic tools, and even drugs.
=== Temperature dependence === The Young's modulus of metals varies with the temperature and can be realized through the change in the interatomic bonding of the atoms, and hence its change is found to be dependent on the change in the work function of the metal. Although classically, this change is predicted through fitting and without a clear underlying mechanism (for example, the Watchman's formula), the Rahemi-Li model demonstrates how the change in the electron work function leads to change in the Young's modulus of metals and predicts this variation with calculable parameters, using the generalization of the Lennard-Jones potential to solids. In general, as the temperature increases, the Young's modulus decreases via
=== Reston virus: monkeys with ebola virus brought to U.S. === In December 1989, several crab-eating macaques with the Zaire ebolavirus were imported from Mindanao in the Philippines to the company's facility in Reston, Virginia. The strain of the virus became known as the Reston virus. It was the first ebola virus that emerged outside of Africa and was also the first known natural infection of ebola virus in nonhuman primates. The facility was abandoned and torn down and the variant turned out to be non-lethal to humans. The incident was an inspiration for The Hot Zone, a book by Richard Preston published in 1994. In March 1996, two macaques that had been shipped to the company's facility in Alice, Texas, tested positive for the Ebola virus from a group of 100 obtained from the same supplier. The virus strain was the same non-lethal Reston virus as in the earlier incident.
Sources: en.wikipedia.org
=== 35 kDa Protein === The lesser known component of the OpLuc enzyme has 320 amino acids with 11 cysteine and 5 leucine molecules. The amino terminus of the protein was experimentally concluded to begin at 39 amino acids. It is thought to stabilize 19 kDa and is not thought to be affect by substrate specificity, however its exact function is not known.
== Biofuels == The depletion of petroleum sources and increase in greenhouse gas emissions in the twenty and twenty-first centuries has been the driving factor behind the development of biofuels from microorganisms. E. coli is currently regarded as the best option for biofuel production because of the amount of knowledge available about its genome. The process converts biomass into fuels, and has proven successful on an industrial scale, with the United States having produced 6.4 billion gallons of bioethanol in 2007. Bioethenol is currently the front-runner for alternative fuel production and uses S.cerevisiae and Zymomonas mobilis to create ethanol through fermentation. However, maximum productivity is limited due to the fact that these organisms cannot use pentose sugars, leading to consideration of E.coli and Clostridia. E.coli is capable of producing ethanol under anaerobic conditions through metabolizing glucose into two moles of formate, two moles of acetate, and one mole of ethanol. While bioethanol has proved to be a successful alternative fuel source on an industrial scale, it also has its shortcomings, namely, its low energy density, high vapor pressure, and hygroscopicity. Current alternatives to bioethanol include biobutanol, biodiesel, propanol, and synthetic hydrocarbons. The most common form of biodiesels is fatty acid methyl esters and current synthesis strategies involve transesterification of triacylglycerols from plant oils.
ISBN 0-89966-613-2 OCLC 68043161 Cooke, James J. The All-Americans at War: The 82nd Division in the Great War, 1917–1918. Westport, Conn: Praeger, 1999. ISBN 0-275-95740-3 OCLC 39210048 Cooksey, Jon. Crossing the Waal: The US 82nd Airborne Division at Nijmegen. Barnsley: Pen and Sword Military, 2005. ISBN 1-84415-228-6 OCLC 57200754 Covington, Henry L. A Fighting Heart, An Unofficial Story of the 82nd Airborne Division. Fayetteville, NC: T. Davis, 1949. OCLC 4139070 Dawson, Buck. Saga of the All American. Atlanta: Albert Love Enterprises, 1946. OCLC 3595988 Francois, Dominique. 82nd Airborne Division 1917–2005. Bayeux: Heimdal, 2006. ISBN 2-84048-215-0 OCLC 64967339 Gavin, James M. On to Berlin: Battles of an Airborne Commander, 1943–1946. New York: Viking Press, 1978. ISBN 0-670-52517-0 OCLC 3204743 Grey, Stephen. Into the Viper's Nest: The First Pivotal Battle of the Afghan War. Minneapolis: Zenith Press, 2010. ISBN 0-7603-3897-3 OCLC 548583278 Heilman, William H. A Pilot's Tale: Flying Helicopters in Vietnam. Hooks, Tex.?: William H. Heilman, 2008. ISBN 1-4357-1185-8 OCLC 671642623 Hoyt, Edwin Palmer. The Invasion Before Normandy: The Secret Battle of Slapton Sands. Lanham, MD: Scarborough House, 1999. ISBN 0-8128-8562-7 OCLC 41712914 Imai, Kesaharu. Grenada : 25 October to 2 November 1983. Tokyo: World Photo Press, 1984. OCLC 16348601 Langdon, Allen. Ready: The History of the 505th Parachute Infantry Regiment, 82nd Airborne Division, World War II. [Fort Bragg, N.C.]: The Division, 1986. OCLC 16221387 Lebenson, Leonard.
Their work paved the way for the later discovery by Archibald Hill and Otto Fritz Meyerhof that a carbohydrate metabolic cycle supplies the energy used for muscle contraction. In 1912 Hopkins published the work for which he is best known, demonstrating in a series of animal feeding experiments that diets consisting of pure proteins, carbohydrates, fats, minerals, and water fail to support animal growth. This led him to suggest the existence in normal diets of tiny quantities of as yet unidentified substances that are essential for animal growth and survival. These hypothetical substances he called "accessory food factors", later renamed vitamins. It was this work that led his being awarded (together with Christiaan Eijkman) the 1929 Nobel Prize in Physiology or Medicine. During World War I, Hopkins continued his work on the nutritional value of vitamins. His efforts were especially valuable in a time of food shortages and rationing. He agreed to study the nutritional value of margarine and found that it was, as suspected, inferior to butter because it lacked the vitamins A and D. As a result of his work, vitamin-enriched margarine was introduced in 1926. Hopkins is credited with the discovery and characterisation in 1921 of glutathione extracted from various animal tissues. At the time he proposed that the compound was a dipeptide of glutamic acid and cysteine. The structure was controversial for many years but in 1929 he concluded that it was a tripeptide of glutamic acid, cysteine and glycine.
Mature HIV protease exists as a 22 kDa homodimer, with each subunit made up of 99 amino acids. A single active site lies between the identical subunits and has the characteristic Asp-Thr-Gly (Asp25, Thr26 and Gly27) catalytic triad sequence common to aspartic proteases. As HIV-1 PR can only function as a dimer, the mature protease contains two Asp25 amino acids, one from each monomer, that act in conjunction with each other as the catalytic residues. Additionally, HIV protease has two molecular "flaps" which move a distance of up to 7 Å when the enzyme becomes associated with a substrate. This can be visualized with animations of the flaps opening and closing.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
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.