This is a working overview of Semax, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-25 and is reviewed periodically as new material appears.
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.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
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.
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.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
=== Binding of substrates and co-substrates === Binding of phosphorylated substrates to distinct regions of the C-lobe has previously been detected by binding of a tungstate derivative (as a phosphate analog). Instead of phospho-primed substrate also the C-terminal regulatory domain of CK1δ is able to bind to this position for the purpose of autoregulatory function. Binding of ATP is mainly mediated via the glycine-rich P-loop (L-12, bridging strands β1 and β2), forming the top cover of the WTP binding site, and the so-called catalytic loop (L-67). Conformational changes affecting the activation loop (L-9D) are related to regulation of kinase activity. When the activation loop moves out of the catalytic site the catalytically relevant DFG motif (Asp-149, Phe-150, and Gly-151) shifts to an internal position. The aspartate residue chelates a Mg2+ ion allowing proper binding and orientation of ATP. Another residue, which is essentially involved in the regulation of kinase activity, but also in forming interactions with small molecule inhibitors, is Met-82, the so-called gatekeeper residue. Directly located within the ATP binding pocket this residue controls access of small molecules to certain binding pockets (selectivity pockets) located beyond the position of the gatekeeper.
A foundation deposit of Naram-Sin was discovered and analysed by king Nabonidus, around 550 BC. who Robert Silverberg thus characterises as the first archaeologist. Not only did he lead the first excavations which were to find the foundation deposits of the temples of Šamaš the sun god, the warrior goddess Anunitu (both located in Sippar), and the sanctuary that Naram-Sin built to the moon god, located in Harran, but he also had them restored to their former glory. He was also the first to date an archaeological artefact in his attempt to date Naram-Sin's temple during his search for it. His estimate was inaccurate by about 1,500 years.
Eddy tried every remedy for her ill health, including a three-month stay at the Vail's Hydropathic Institute in Hill, New Hampshire. She told the Boston Post in 1883 that, for the seven years prior to 1862 (most of her second marriage), she had been effectively confined to her bed or room. In 1861 Eddy heard of a healing method developed by Phineas Parkhurst Quimby, a former clockmaker in Portland, Maine. Self-styled Dr. P. P. Quimby, a practitioner of the "Science of Health," had become interested in healing after recovering suddenly from a condition he believed was consumption (tuberculosis). After attending a lecture in Maine in 1837 by the French mesmerist Charles Poyen, Quimby began to practice mesmerism himself. Mesmerism was named after Franz Mesmer (1734–1815), a German physician who argued for the existence of a fluid through which bodies could influence each other, a force he called animal magnetism. Quimby and an assistant, Lucius Burkmar, traveled around Maine and New Brunswick giving demonstrations; Burkmar, in a trance, would offer mind readings and suggestions for cures. Quimby abandoned mesmerism around 1847 when he realized that it was suggestion that was effecting the apparent cures. He came to the view that disease was a mental state. When Jesus healed a paralysed arm, he had known, Quimby wrote, "that the arm was not the cause but the effect, and he addressed Himself to the intelligence, and applied His wisdom to the cause".
==== Dengue epidemic ==== In 2024, the number of deaths from dengue in the country surged (6,041), an increase of 400% compared with 2023 (1,179), surpassing the deaths from COVID-19 (5,960) in that year (2024). Dengue deaths in 2024 exceeded the total for the previous eight years (4,992). The explosion in dengue cases led opposition deputies from the PL to nickname Lula "presidengue" and share false and exaggerated data about the number of deaths resulting from this small-scale epidemic.
Sources: en.wikipedia.org
Before the 20th century crystallography was not a well-established academic discipline. There were no academic positions specifically in crystallography. Workers in the field normally carried out their crystallographic research as an ancillary to other employment(s), or had independent means. The leading workers in the field of chemical crystallography were employed as follows:
German-made Leopard tanks from Warsaw arrived in Ukraine as Polish Prime Minister Mateusz Morawiecki visited Kyiv to send a "clear and measurable signal of further support". The United States authorized $2 billion in aid to Ukraine, and ramped up sanctions and tariffs on Russia. The weapons package announced by the Defense Department included funding for contracts for HIMARS rockets, drones and counter-drone equipment, mine-clearing devices, 155-millimeter artillery ammunition and secure lines of communication. China proposed a peace plan which involves a ceasefire and multiple other steps that would result in direct negotiations. China holds the stance about "countries' sovereignty, independence and territorial integrity be effectively guaranteed" and that the "cold war mentality" should end. US officials such as President Biden and Secretary of State Antony Blinken expressed doubts about the plan, citing doubts over its neutrality and its failure to condemn the invasion. Zelenskyy stated that it was good that China is talking about Ukraine, but that he would cautiously await details on the plan. It was also speculated by some experts that depending on how this turns out, China could also turn around and start supplying Russia with military equipment.
Etymology The term poultice comes from the Latin puls or pultēs, meaning "porridge" or "thick pap," through Middle English pultes. This reflects the traditional preparation of poultices as soft, moist masses resembling porridge. Ancient use Poultices have been documented in many ancient medical traditions, including Egypt, Mesopotamia, India, Greece, and Rome. They were usually made from plants, animal products, or minerals, and applied directly to the skin to reduce pain, inflammation, or infection.
The album fused together the Reids' two primary influences: the guitar noise of the Stooges and the Velvet Underground with the pop songwriting and melodies of the Beach Boys, The Shangri-Las and Phil Spector; In fact, the album's opening song, "Just Like Honey," borrows Hal Blaine's famous drum intro from The Ronettes 1963 classic, "Be My Baby", produced and co-written by Spector. The record received unanimously positive reviews and is now considered a landmark recording. Drummer Gillespie announced his departure from the band in October 1985, to concentrate on Primal Scream. He had recorded most of the drums on Psychocandy, with John Moore filling in when Gillespie was unavailable, eventually joining the band to replace him. John Loder also acted as a stand-in drummer when Gillespie was unavailable for live performances. When the band signed to Blanco y Negro in January 1985, there were stories reporting that they had stolen money from managing Director Rob Dickens's jacket and destroyed his office, all untrue but seen as good publicity by manager McGee. In a performance on Belgian television in March 1985, the band did smash the set and the audio equipment, but this was at the request of the TV producer. Such behaviour became expected of the band and many shows culminated with the Reids trashing their equipment, which was often followed by the audience throwing projectiles onto the stage and damaging equipment. On 15 March 1985, the Jesus and Mary Chain played a gig at the North London Polytechnic in front of one of their largest crowds up to that point.
==== China ==== Many Chinese tofu dishes such as jiācháng dòufu (家常豆腐) and mapo tofu (麻婆豆腐) may include meat. In Chinese cuisine, Dòuhuā (豆花) is served with toppings such as boiled peanuts, azuki beans, cooked oatmeal, tapioca, mung beans, or a syrup flavored with ginger or almond. During the summer, "dòuhuā" is served with crushed ice; in the winter, it is served warm. In many parts of China, fresh tofu is eaten with soy sauce or further flavored with katsuobushi shavings, century eggs (皮蛋 pídàn), and sesame seed oil. With the exception of the softest tofus, all forms of tofu can be fried. Thin and soft varieties of tofu are deep fried in oil until they are light and airy in their core 豆泡 dòupào, 豆腐泡 dòufupào, 油豆腐 yóudòufu, or 豆卜 dòubǔ in Chinese, literally "bean bubble", describing the shape of the fried tofu as a bubble. Depending on the type of tofu used, the texture of deep-fried tofu may range from crispy on the outside and custardy on the inside, to puff up like a plain donut. The former is usually eaten plain in Chinese cuisine with garlic soy sauce, while the latter is either stuffed with fish paste to make Yong Tau Foo or cooked in soups. In Taiwan, fried tofu is made into a dish called "A-gei", which consists of a fried aburage tofu package stuffed with noodles and capped with surimi. Tofus such as firm East Asian and dòugān (Chinese dry tofu), with their lower moisture content, are cut into bite-sized cubes or triangles and deep fried until they develop a golden-brown, crispy surface (炸豆腐 in Chinese, zhádòufu, lit. "fried tofu").
Sources: en.wikipedia.org
=== Quartz fiber filter === Quartz fiber filter paper has a high resistance to chemicals, does not absorb NOx and SOx dioxides, is unaffected by humidity and is easily sterilized. Thus, it is mostly used for air pollution analysis.
Qullqa's were generally built of masonry in connected groups on dry hillsides to take advantage of drainage and winds. Their size and design varied from region to region, but round qullqas were typically used to store maize and rectangular qullqas were used to store freeze-dried potatoes ("chuño") and other root crops. Qullqas had a ventilation system consisting of a channel beneath the floor to permit air to enter and an opening under the roof to allow air to escape. The interior diameter of an average small qullqa was 3.23 metres (10.6 ft); larger qullqas have a diameter of around 3.5–4.0 metres (11.5–13.1 ft). These smaller qullqa could have held 3.7 cubic metres (100 US bushels) of maize, and larger qullqa could have held about 5.5 cubic metres (160 US bushels) of maize. Most of the remains of qullqas near Cuzco have disappeared due to urban expansion and development over the centuries. The largest remaining number of qullqas is in the Mantaro River valley between the present days cities of Huancayo and Jauja, Peru. This broad valley, some 60 kilometres (37 mi) long contains about 65,000 hectares (160,000 acres) of cultivatable lands ranging in elevation from 3,200 metres (10,500 ft) to 4,250 metres (13,940 ft), the highest elevation at which cultivation was possible in this area. The Mantaro Valley was one of the largest and most fertile high-altitude areas of the Inca Empire. 2,573 qullqas have been found in the valley by archaeologists.
The Aleutians are home to many large colonies of seabirds. Buldir Island has 21 breeding seabird species, including the Bering Sea-endemic red-legged kittiwake. Large seabird colonies are also present at Kiska, Gareloi, Semisopochnoi, Bogoslof, and others. The islands are also frequented by vagrant Asiatic birds, including the common rosefinch, Siberian rubythroat, bluethroat, lanceolated warbler, and the first North American record of the intermediate egret. The habitats of the Aleutians are largely unspoiled, but wildlife is affected by competition from introduced species such as cattle, caribou, and foxes. Nearly all of the Aleutians are protected as part of the Alaska Maritime National Wildlife Refuge and the Aleutian Islands Wilderness. Observations have identified sea otters as a keystone species along the coasts of many of the Aleutian Islands. Their presence encourages the growth of kelp forests, as the otters control sea urchin populations (as large populations of sea urchins can create urchin barrens by clearing away kelp stands).
Proteins that are destined for degradation by the 26S proteasome require two main elements: 1) the attachment of a small protein called ubiquitin and 2) an unstructured region of about 25 amino acids. Proteins that lack this unstructured region can have another motor, cdc48 in yeast or P97 in humans, generate this unstructured region by a unique mechanism where ubiquitin is unfolded by cdc48 and its cofactors Npl4/Ufd1. The tagging of a target protein by ubiquitin is catalyzed by cascade of enzymes consisting of the Ubiquitin-activating enzyme (E1), Ubiquitin-conjugating enzyme (E2), and ubiquitin ligases (E3). Once a protein is tagged with a single ubiquitin molecule, this is a signal to other ligases to attach additional ubiquitin molecules. The result is a polyubiquitin chain that is bound by the proteasome, allowing it to degrade the tagged protein in an ATP dependent manner. The degradation process by the proteasome yields peptides of about seven to eight amino acids long, which can then be further degraded into shorter amino acid sequences and used in synthesizing new proteins.
This convinced Macleod to divert the whole laboratory to insulin research and to bring in the biochemist James Collip to help with purifying the extract. The first human clinical trial was unsuccessful. Banting was insufficiently qualified to participate and felt sidelined. By the winter of 1922, he was certain that all Macleod's colleagues were conspiring against him. There was a reported physical altercation between Banting and Collip, as Banting saw Collip's breakthrough on alcohol purification as a threat, while Collip was reluctant to share the details. Collip threatened to leave because of the strained atmosphere but the encouragement of others who saw the potential of their research prevented escalation of the conflict. In January 1922, the team performed the first successful clinical trial, on 13-year-old Leonard Thompson, and it was soon followed by others. Although all the team members were listed as co-authors of their publications, Banting still felt overlooked, because Macleod took over the coordination of clinical trials and the acquisition of larger amounts of extract. Macleod's presentation at a meeting of the Association of American Physicians in Washington, D.C., on 3 May 1922 received a standing ovation, but Banting and Best refused to participate in protest. At that time, demonstrations of the method's efficiency drew huge public interest, because the effect on patients, especially children, who until then were bound to die, seemed almost miraculous. The pharmaceutical company Eli Lilly & Co.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.