A practical reference on Semax: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-04-26. Anything still debated is marked as such rather than presented as settled.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
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 |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
=== Metabolism === B. canis functions as a chemoorganotroph, deriving energy from the oxidation of organic compounds and utilizing organic electron sources. Studies indicate that B. canis, like other Brucella species, shares a conserved metabolic architecture within the genus. This includes a lack of phosphofructokinase (PFK), an enzyme required for the Embden–Meyerhof–Parnas (EMP) pathway (classical glycolysis). Instead, glucose catabolism is accomplished using the pentose phosphate pathway. While select Brucella species can also rely on a functional Entner–Doudoroff pathway, this pathway is not functional in most Brucella species, including B. canis, due to inactivating mutations. B. canis also possesses a complete tricarboxylic acid (TCA) cycle, which primarily utilizes oxygen as its terminal electron acceptor within its electron transport chain. In anaerobic conditions, nitrate can also function as a terminal electron acceptor because B. canis is capable of producing nitrate reductase. B. canis also exhibits strong urease activity, producing the enzyme urease to hydrolyze urea into ammonia and carbon dioxide. This enzymatic activity is relevant for its role in nitrogen acquisition and as a notable virulence factor, as it helps to neutralize and facilitate survival within surrounding acidic environments. For laboratory identification, a relevant metabolic characteristic of B. canis is that it does not require supplemental CO2 for growth, unlike some other Brucella species. Additionally, B.
=== Environmental disturbance === American kestrels' response to environmental stress is measured as blood concentration of corticosterone (CORT), a hormone produced by the hypothalamic-pituitary-adrenal (HPA) axis that releases stored energy for essential body functions. Extended periods of elevated blood CORT levels may direct metabolic energy away from growth and reproduction. Thus, high levels of traffic disturbance and human development surrounding American kestrel nests are found to increase stress hormones leading to reproductive failure. Among successful nests, however, nestlings do not typically experience a higher stress response to environmental human disturbance, suggesting that they can tolerate a considerable degree of human activity near the nest.
3D Realms was eventually acquired in part by Interceptor Entertainment, and in 2014, Interceptor announced plans to make a new Duke Nukem game, Duke Nukem: Mass Destruction. Gearbox filed suit against 3D Realms and Interceptor based on the fact that Gearbox now owned the rights to the Duke Nukem franchise. The case was settled out of court in August 2015, with 3D Realms and Interceptor acknowledging that Gearbox has full rights to the Duke Nukem series. Following the settlement, Gearbox released Duke Nukem 3D: 20th Anniversary Edition World Tour in September 2016. The game included new levels developed in conjunction with some of the original developers, re-recorded lines by original Duke voice actor Jon St. John, and new music from original composer Lee Jackson. It was released on October 11, 2016.
Sources: en.wikipedia.org
Traditionally the inherited metabolic diseases were classified as disorders of carbohydrate metabolism, amino acid metabolism, organic acid metabolism, or lysosomal storage diseases. In recent decades, hundreds of new inherited disorders of metabolism have been discovered and the categories have proliferated. Following are some of the major classes of congenital metabolic diseases, with prominent examples of each class.
== History == The structure of TRH was first determined, and the hormone synthesized, by Roger Guillemin and Andrew V. Schally in 1969. Both parties insisted their labs determined the sequence first: Schally first suggested the possibility in 1966, but abandoned it after Guillemin proposed TRH was not actually a peptide. Guillemin's chemist began concurring with these results in 1969, as NIH threatened to cut off funding for the project, leading both parties to return to work on synthesis. Schally and Guillemin shared the 1977 Nobel Prize in Medicine "for their discoveries concerning the peptide hormone production of the brain." News accounts of their work often focused on their "fierce competition" and use of a very large number of sheep and pig brains to locate the hormone.
=== Causes and risks === Noma is an opportunistic rather than contagious infection. No single pathogen has been associated with the disease (the causative organisms are common in many environments) and there are no documented cases of person to person transmission. The underlying causes for this disease are extreme poverty, malnutrition, other causes of immunosuppression, underlying infections, and poor oral health. The disease principally affects extremely impoverished and malnourished children between 2 and 6 years old in tropical regions. Cases of noma have also been reported in malnourished or immunosuppressed adults, and in concentration camps during the Second World War. Predisposing factors include:
Sources: en.wikipedia.org
== Uses == In the 1970s and 1980s, the proportionately largest use of these polymers was in water treatment. The next major application by weight is additives for pulp processing and papermaking. About 30% of polyacrylamide is used in the oil and mineral industries.
Trans fat is a type of unsaturated fat that occurs in foods. Trans fats are fats (triglycerides, i.e. triple esters of glycerin) that contain chains derived from trans fatty acids. Trans fatty acids are unsaturated fatty acids that contain a double bond in the trans conformation. Small amounts of trans fats occur naturally in animal and dairy products, but large amounts are found in some processed foods made with partially hydrogenated oils. Because consumption of trans fats is associated with increased risk for cardiovascular diseases, artificial trans fats are highly regulated or banned in many countries. However, they are still widely consumed in developing nations where they are associated with increased risk of diabetes, cardiovascular diseases, and death. In 2015, the US Food and Drug Administration (FDA) determined that artificial trans fats made from partially hydrogenated oils (PHOs) were not generally recognized as safe. As a result, these oils were banned from foods sold in the US beginning June 18, 2018, with limited extensions for specific, approved uses until 2020 or 2021. Following the US action, other governing bodies, including the European Union, Canada, Australia, and New Zealand introduced restrictions or bans on the use of partially hydrogenated oils and industrial trans fats in food manufacturing. The World Health Organization (WHO) set a global goal to eliminate industrially produced trans fat by the end of 2023. The goal was not fully achieved.
As a result of his later work he proved that wide differences exist between different food proteins; and he was the first to direct attention to this fact, and to discuss its probable bearing on their relative value in nutrition. Osborne then joined forces with Lafayette Mendel at the Connecticut Agricultural Experiment Station to determine the essential amino acids. In the 1950s and 1960s, Nevin S. Scrimshaw took this knowledge to India and Guatemala. He designed meals using local vegetables to fight against the scourge of kwashiorkor. In Guatemala he used the combination of cottonseed flour with maize, while in India he combined peanut flour with wheat.
Heseltine played an important role in taking charge of the Millennium Exhibition in Greenwich and ensuring that it happened, even having a meeting with Tony Blair, Leader of the Opposition, in January 1997 to agree that a Labour Government would back it.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
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.