Everything below concerns Heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
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 |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
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.
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.
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.
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.
=== Disease association === Genetic activation of NRF2 has been implicated in the development of de novo tumors, as well as in the progression of atherosclerosis by increasing plasma cholesterol levels and hepatic cholesterol content. It has been suggested that these pro-atherogenic effects may outweigh the protective benefits of NRF2-mediated antioxidant induction.
Archaeological evidence from sites in the United States, Mexico, and Peru indicates that mescaline-containing cacti have been used for over 6,000 years. Europeans recorded use of peyote in Native American religious ceremonies upon early contact with the Huichol people in Mexico. Other mescaline-containing cacti such as the San Pedro cactus have a long history of use in South America, from Peru to Ecuador. While religious and ceremonial peyote use was widespread in the Aztec Empire and northern Mexico at the time of the Spanish conquest, religious persecution confined it to areas near the Pacific coast and up to southwest Texas. However, by 1880, peyote use began to spread north of South-Central America with "a new kind of peyote ceremony" inaugurated by the Kiowa and Comanche people. These religious practices, incorporated legally in the United States in 1920 as the Native American Church, have since spread as far as Saskatchewan, Canada.
== Pentachlorophenol by country == Pentachlorophenol is classified as a persistent organic pollutant (POP). In May 2015, countries which have signed the Stockholm Convention voted 90–2 to ban pentachlorophenol use. The United States is not a signatory and has not banned the chemical.
=== Single Convention on Narcotic Drugs, 1961 === The adoption of this convention is regarded as a milestone in the history of the international drug ban. The Single Convention codified all existing multilateral treaties on drug control and extended the existing control systems to include the cultivation of plants that were grown as the raw material of narcotic drugs. The principal objectives of the convention are to limit the possession, use, trade, distribution, import, export, manufacture, and production of drugs exclusively for medical and scientific purposes, and to address drug trafficking through international cooperation to deter and discourage drug traffickers. The convention also established the International Narcotics Control Board, merging the Permanent Central Board and the Drug Supervisory Board. The 1961 Convention seeks to control over 116 drugs that it classifies as narcotic. These include:
==== Naldemedine ==== Naldemedine has a similar chemical structure as naltrexone but with an additional side chain that increases the molecular weight and polar surface area of the substance. Like naloxegol, naldemedine is a substrate of the P-glycoprotein efflux transporter. These properties result in less penetration into the CNS and decrease possible inference with the effects of opioid agonists. Naldemedine is a dual antagonist for MOR and DOR. Activation of the DOR has been known to cause nausea and/or vomiting, so a dual antagonist can decrease both OIC and nausea/vomiting.
Sources: en.wikipedia.org
Articular discs or menisci - the fibrocartilage pads between opposing surfaces in a joint Articular fat pads - adipose tissue pads that protect the articular cartilage, as seen in the infrapatellar fat pad in the knee Tendons - cords of dense regular connective tissue composed of parallel bundles of collagen fibers Accessory ligaments (extracapsular and intracapsular) - the fibers of some fibrous membranes are arranged in parallel bundles of dense regular connective tissue that are highly adapted for resisting strains to prevent extreme movements that may damage the articulation Bursae - sac-like structures that are situated strategically to alleviate friction in some joints (shoulder and knee) that are filled with fluid similar to synovial fluid The bone surrounding the joint on the proximal side is sometimes called the plafond (French word for ceiling), especially in the talocrural joint. Damage to this structure is referred to as a Gosselin fracture.
The main role of a sinoatrial node cell is to initiate action potentials of the heart that can pass through cardiac muscle cells and cause contraction. An action potential is a rapid change in membrane potential, produced by the movement of charged atoms (ions). In the absence of stimulation, non-pacemaker cells (including the ventricular and atrial cells) have a relatively constant membrane potential; this is known as a resting potential. This resting phase (see cardiac action potential, phase 4) ends when an action potential reaches the cell. This produces a positive change in membrane potential, known as depolarization, which is propagated throughout the heart and initiates muscle contraction. Pacemaker cells, however, do not have a resting potential. Instead, immediately after repolarization, the membrane potential of these cells begins to depolarise again automatically, a phenomenon known as the pacemaker potential. Once the pacemaker potential reaches a set value, the threshold potential, it produces an action potential. Other cells within the heart (including the Purkinje fibers and atrioventricular node) can also initiate action potentials; however, they do so at a slower rate and therefore, if the SA node is functioning properly, its action potentials usually override those that would be produced by other tissues. Outlined below are the 3 phases of a sinoatrial node action potential. In the cardiac action potential, there are 5 phases (labelled 0-4), however pacemaker action potentials do not have an obvious phase 1 or 2. Phase 4
=== Water treatment === Metal–organic frameworks (MOFs) have attracted increasing attention as functional materials for water treatment due to their high surface area, tunable pore structures, and chemical versatility. These properties enable MOFs to act as efficient platforms for the removal of a wide range of contaminants from aqueous systems. In particular, MOFs have been extensively investigated for the adsorption of heavy metal ions such as lead, chromium, arsenic, and cadmium , as well as for the removal of organic pollutants including dyes, pesticides, and pharmaceutical residues. In water treatment applications, adsorption is one of the primary mechanisms by which MOFs operate. The porous structure of MOFs provides abundant active sites for interaction with pollutants, while the ability to tailor the chemical functionality of the framework allows for selective binding through coordination interactions, electrostatic attraction, and hydrogen bonding. This tunability has enabled the design of MOFs with enhanced selectivity toward specific contaminants, making them promising candidates for targeted water purification. Beyond adsorption, MOFs have also been explored in membrane-based separation processes and as catalytic materials for the degradation of pollutants. For example, MOF-based membranes have demonstrated potential for selective ion separation and removal of dissolved contaminants, while photocatalytic and advanced oxidation processes involving MOFs have been used to degrade persistent organic pollutants into less harmful species.
Construction was interrupted by Cuba's involvement in World War I, but it was completed on February 9, 1920. On opening day, hundreds of visitors from around Havana and the surrounding areas came to tour the facility, including the Provincial Governor of Havana, Colonel Alberto Barreras, who was also a Freemason. Governor Barrearas oversaw a twelve gun salute and a performance of La Bayamesa by the General Staff Band. Three flags were raised; the flag of Cuba, the flag of the Supreme Council of Cuba, and the flag of the Grand Lodge of Cuba. Priority was given to Freemasons, but anyone could apply for housing here. There were only four rules needed to become a resident here: Residents had to be someone who needed public charity to live, "...even if they got there through vices." Residents had to be homeless. If the resident wasn't a Freemason, they needed to have letters of recommendation. All residents needed to pay up to 100 dollars to secure housing. As the years went by, the name "Asilo," or Asylum, became increasingly problematic. The original business model of the Mercy Asylum under its previous owners from 1886 had been to take beggars off of the street and put them into the shelter. As Cuba's new sphere of academia and the social welfare science studies advanced, earlier common practices in charity and relief work were radically transformed. Around the world, people began associating the term asylum with places like Bellevue Hospital and Bethlem Royal Hospital, and the Freemasons wanted to avoid that association.
Sources: en.wikipedia.org
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
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.