The short version of Tuftsin analogue fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-10-24. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| 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 |
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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. 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.
Selenium shows borderline metalloid or nonmetal behaviour. Its most stable form, the grey trigonal allotrope, is sometimes called "metallic" selenium because its electrical conductivity is several orders of magnitude greater than that of the red monoclinic form. The metallic character of selenium is further shown by its lustre, and its crystalline structure, which is thought to include weakly "metallic" interchain bonding. Selenium can be drawn into thin threads when molten and viscous. It shows reluctance to acquire "the high positive oxidation numbers characteristic of nonmetals". It can form cyclic polycations (such as Se2+8) when dissolved in oleums (an attribute it shares with sulfur and tellurium), and a hydrolysed cationic salt in the form of trihydroxoselenium(IV) perchlorate [Se(OH)3]+·ClO–4. The nonmetallic character of selenium is shown by its brittleness and the low electrical conductivity (~10−9 to 10−12 S•cm−1) of its highly purified form. This is comparable to or less than that of bromine (7.95×10–12 S•cm−1), a nonmetal. Selenium has the electronic band structure of a semiconductor and retains its semiconducting properties in liquid form. It has a relatively high electronegativity (2.55 revised Pauling scale). Its reaction chemistry is mainly that of its nonmetallic anionic forms Se2−, SeO2−3 and SeO2−4. Selenium is commonly described as a metalloid in the environmental chemistry literature.
Insulin-like growth factor 1 (IGF1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults. In the 1950s IGF1 was called "sulfation factor" because it stimulated sulfation of cartilage in vitro, and in the 1970s due to its effects it was termed "nonsuppressible insulin-like activity" (NSILA). IGF1 is a protein that in humans is encoded by the IGF1 gene. IGF1 consists of 70 amino acids in a single chain with three intramolecular disulfide bridges. IGF1 has a molecular weight of 7,649 daltons. In dogs, an ancient mutation in IGF1 is the primary cause of the toy phenotype. IGF1 is produced primarily by the liver. Production is stimulated by growth hormone (GH). Most of IGF1 is bound to one of 6 binding proteins (IGF-BP). IGFBP-1 is regulated by insulin. IGF1 is produced throughout life; the highest rates of IGF1 production occur during the pubertal growth spurt. The lowest levels occur in infancy and old age. Low IGF1 levels are associated with cardiovascular disease, while high IGF1 levels are associated with cancer. Mid-range IGF1 levels are associated with the lowest mortality. A synthetic analog of IGF1, mecasermin, is used for the treatment of growth failure in children with severe IGF1 deficiency. Cyclic glycine-proline (cGP) is a metabolite of hormone insulin-like growth factor-1 (IGF1).
=== Preservatives and Antioxidants === Oils and fats used in topical cream formulations are susceptible to oxidation by atmospheric oxygen or microorganism action. The stability against oxidation can be enhanced by the introduction of antioxidants. The selection of antioxidants and their concentration can only be determined by testing their effectiveness on the final product, according to pharmacopoeial information. The efficiency of antioxidants depends on their compatibility with other excipients and oil/water partition coefficient. Oxidations from microbiological source influence the physicochemical properties of the emulsion, resulting in color and odor changes, fat and oil hydrolysis, pH changes in the aqueous phase, or phase separation of the cream. Oil-in-water creams are more susceptible to microbial contamination. Therefore, preservatives are included to prevent any microorganism growth. Preservatives suitable for topical cream formulations must present a broad spectrum of bactericidal activity, low logP, compatibility with other excipients, stability, and effectiveness over a wide range of pH and temperatures.
=== Bacterial homeostasis === AMPylation is involved in bacterial homeostasis. The most famous example is AMPylator GS-ATase (GlnE), which contributes in complex regulation of nitrogen metabolism through AMPylation of glutamine synthetase that was introduced in the AMPylation and DeAMPylation parts. Another example of AMPylators that play a role in bacterial homeostasis is the class I Fic AMPylators (FicT), which modifies the GyrB subunit of DNA gyrase, the conserved tyrosine residue for ATP binding of ParE subunit at Topoisomerase IV. This DNA gyrase inactivation by AMPylation leads to the activation of SOS response, which is the cellular response to DNA damage. The activity of FicT AMPylation is reversible and only leads to growth arrest, but not cell death. Therefore, FicT AMPylation plays a role in regulating cell stress, which is shown in the Wolbachia bacteria that the level of FicT increases in response to doxycycline. A Class III Fic AMPylator NmFic of N. meningtidis is also found to modify AMPylate GyrB at the conserved tyrosine for ATP binding. This shows that Fic domains are highly conserved that indicates the important role of AMPylation in regulating cellular stress in bacteria. The regulation of NmFic involves the concentration-dependent monomerization and autoAMPylation for activation of NmFic activity.
Sources: en.wikipedia.org
In 1983, financier Marc Rich was accused of violating the act by trading in Iranian oil during the Iran hostage crisis. He was one of many people pardoned by President Bill Clinton in his last days in office. On August 23, 2006, Javed Iqbal was arrested through the U.S. Department of the Treasury with a charge of conspiracy to violate the IEEPA for airing material produced by al-Manar (The Beacon) in New York City during the 2006 Israel-Lebanon conflict. On December 16, 2009, it was announced that the U.S. Department of Justice reached a settlement with Credit Suisse over accusations that the bank assisted residents of IEEPA sanctioned countries to wire money in violation of the Act from 1995 to 2006. The settlement resulted in Credit Suisse forfeiting $536 million. On July 16, 2020, a UAE-based firm, Essentra FZE Company Limited, admitted of conspiring to violate the International Emergency Economic Powers Act (IEEPA) and defying the United States sanctions on North Korea. The firm also agreed to pay a fine of $665,112 to the United States Department of Justice.
=== Neurocognitive safety === Studies of SSRIs in patients with major psychiatric disorders prove that SSRIs are potentially associated with certain neurocognitive adverse effects such as anxiety, akathisia, hypomania, changes in mood, or suicidal thought. No study on the effects of SSRIs in men with PE has been done. McMahon's study in 2012 showed that dapoxetine has no effect on mood and is not associated with anxiety or suicidality.
=== 1975 === January 3: The Trade Act of 1974, including the Jackson–Vanik amendment, is signed into law in the United States. April 13: Tensions between the Maronite Christians and Muslims ignited the Lebanese Civil War. April 18: The communist Khmer Rouge, under the leadership of Pol Pot, take power in Cambodia. Beginning of the Cambodian genocide. April 30: North Vietnam wins the Vietnam War. The South Vietnam regime falls with the surrender of Saigon and the two countries are later united under a communist government. May 12: Mayagüez incident: the Khmer Rouge seize an American naval ship, prompting American intervention to recapture the ship and its crew. In the end, the crew is released from captivity. June 8: Venera 9, a Soviet uncrewed space mission to Venus, is launched. June 25: Portugal withdraws from Angola and Mozambique, where Marxist governments are installed, the former with backing from Cuban troops. Civil war engulfs both nations and involves Angolans, Mozambicans, South Africans, and Cubans, with the superpowers supporting their respective ideologies. July 5: Cape Verde becomes independent from Portugal. July 6: Comoros becomes independent from France. July 12: São Tomé and Príncipe becomes independent from Portugal. July 15: The Apollo-Soyuz Test Project takes place. It is the first joint flight of the US and Soviet space programs. The mission is seen as a symbol of détente and an end to the "space race".
Having discovered North America instead, on his return Cabot spoke of the great quantities of cod to be found near the new land. In 1498 Cabot set sail again from Bristol with an expedition of five ships and is believed to have never returned from this voyage, although recent research conducted at the University of Bristol, suggests that he might have. From 1499 to 1508 a number of other expeditions were launched from Bristol to the 'New found land', the earliest being undertaken by William Weston. One of these, led by John Cabot's son, Sebastian Cabot, explored down the coast of North America until he was 'almost in the latitude of Gibraltar' and 'almost the longitude of Cuba'. This would suggest that he reached as far as the Chesapeake, close to what is now Washington D.C.
=== Poroelasticity === Poroelasticity is a characteristic of materials related to the migration of solvent through a porous material and the concurrent deformation that occurs. Poroelasticity in hydrated materials such as hydrogels occurs due to friction between the polymer and water as the water moves through the porous matrix upon compression. This causes a decrease in water pressure, which adds additional stress upon compression. Similar to viscoelasticity, this behavior is time dependent, thus poroelasticity is dependent on compression rate: a hydrogel shows softness upon slow compression, but fast compression makes the hydrogel stiffer. This phenomenon is due to the friction between the water and the porous matrix is proportional to the flow of water, which in turn is dependent on compression rate. Thus, a common way to measure poroelasticity is to do compression tests at varying compression rates. Pore size is an important factor in influencing poroelasticity. The Kozeny–Carman equation has been used to predict pore size by relating the pressure drop to the difference in stress between two compression rates. Poroelasticity is described by several coupled equations, thus there are few mechanical tests that relate directly to the poroelastic behavior of the material, thus more complicated tests such as indentation testing, numerical or computational models are utilized. Numerical or computational methods attempt to simulate the three dimensional permeability of the hydrogel network.
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.
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.