If you have been reading about tuftsin and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-02-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
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.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
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.
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.
Goodman impelled technical and procedural progress and popularized the open rhinoplasty approach. In 1987, Gunter reported the technical effectiveness of the open rhinoplasty approach for performing a secondary rhinoplasty; his improved techniques advanced the management of a failed nose surgery. In early 2021, it was reported that a trend that involved getting a rhinoplasty had emerged on the social media platform TikTok. The trend became known as the #NoseJobCheck trend and involved users of the platform posting videos that showed how their noses looked before and after their rhinoplasty surgeries, with a specific audio soundtracking the video. From October 2020 to January 2021, the #NoseJobCheck audio had been used in over 120,000 videos and videos with the #NoseJobCheck hashtag had accumulated over one billion views.
The safe storage of food for home use should strictly adhere to guidelines set out by reliable sources, such as the United States Department of Agriculture or the European Food Safety Authority. Scientists have thoroughly researched these guidelines to determine the most effective methods for reducing the real threat of food poisoning caused by unsafe food storage. It is also important to maintain proper kitchen hygiene to reduce the risk of bacterial or viral growth and food poisoning. The common food poisoning illnesses include Listeriosis, Mycotoxicosis, Salmonellosis, E. coli, Staphylococcal food poisoning and Botulism. Many other organisms can also cause food poisoning. There are also safety guidelines for the correct methods of home canning. For example, there are specific boiling times that apply depending upon whether pressure canning or waterbath canning is being used in the process. These safety guidelines are intended to reduce the growth of mold and bacteria and the threat of potentially fatal food poisoning.
Eastern tribes in the mainland US also traded tobacco as a trade item in exchange for food, clothing, beads, and salt, and would often smoke tobacco during sacred and ritualized ceremonies using pipes. Tobacco was considered to be a gift from the gods and it was believed that the exhaled tobacco smoke generated from smoking a pipe would carry one's thoughts and prayers to the creator up above in the heavens. Toboggan – the Innu and the Cree nations of Canada developed a sled in the form of the toboggan. These sleds were used to transport people and cargo across the snow using dogs as draft animals. Sled dogs such as Huskies were used to pull the dog sled along the harsh Canadian winter snows. Toggling harpoon – first used by the Red Paint People of the North American east coast, they were later used by the Thule. Tomato – indigenous Americans were the first peoples in the world to domesticate and cultivate the tomato by 500 BCE. The tomato was an essential ingredient that formed the basis of many indigenous foods including tamales, tostado, soups, and salads. Tomahawk - created originally by the Algonquian people before the arrival of Europeans, the Tomahawk would then later spread from the Algonquian culture to tribes in the South and Great Plains. Tortillas – this staple food well known today was used throughout Mesoamerican and Southwestern US cultures. Although they were mainly made of corn, squash and amaranth were also popular. The tortillas were wrapped around different fillings such as avocado.
Sources: en.wikipedia.org
τν is the spectral optical depth in frequency, and τλ is the spectral optical depth in wavelength. Although absorbance is properly unitless, it is sometimes reported in "absorbance units", or AU. Many people, including scientific researchers, wrongly state the results from absorbance measurement experiments in terms of these made-up units.
== Education == Smith obtained his B.S. in chemistry in 1971 from Lowell Technological Institute (currently the University of Massachusetts Lowell). He then received his PhD in the field of Physical Chemistry from the University of Utah in 1975.
The peptide bonds in the chain are polar, i.e. they have separated positive and negative charges (partial charges) in the carbonyl group, which can act as hydrogen bond acceptor and in the NH group, which can act as hydrogen bond donor. These groups can therefore interact in the protein structure. Proteins consist mostly of 20 different types of L-α-amino acids (the proteinogenic amino acids). These can be classified according to the chemistry of the side chain, which also plays an important structural role. Glycine takes on a special position, as it has the smallest side chain, only one hydrogen atom, and therefore can increase the local flexibility in the protein structure. Cysteine in contrast can react with another cysteine residue to form one cystine and thereby form a cross link stabilizing the whole structure. Protein structure arises from a sequence of secondary structure elements, such as α helices and β sheets. In secondary structures, regular patterns of H-bonds are formed between the main chain NH and CO groups of spatially neighboring amino acids, and the amino acids have similar Φ and ψ angles.
Hunt Sahir Field in December 1971. In September 1973, all foreign oil producers in Libya saw 51 per cent of their operation nationalized. Among the companies that were partially nationalized was Armand Hammer's Occidental Petroleum. For Gaddafi, this was an essential step towards socialism. It proved an economic success; while gross domestic product had been $3.8 billion in 1969, it had risen to $13.7 billion in 1974, and $24.5 billion in 1979. In turn, Libyan standards of life greatly improved over the first decade of Gaddafi's administration, and by 1979 the average per-capita income was at $8,170, up from $40 in 1951; above that of many industrialized countries like Italy and the UK. In 1969, the government ordered all foreign owned banks to close down or convert to joint-stock operations.
Sources: en.wikipedia.org
An identical band was found doing the reverse order of the detection; meaning Myc antibody was immunoprecipitated then followed by blotting with the HA antibody. So, the method had proven to work that photo-Met could cross-link proteins, but the physiological implications of this cross-linking has yet to be determined.
Half-Life 2 has an aggregate score of 96/100 on Metacritic based on 81 reviews. Sources such as 1UP, GameSpy, The Cincinnati Enquirer, The New York Times, and VideoGamer.com gave it perfect scores, and others, such as PC Gamer, IGN, GamesRadar, and Eurogamer, gave near-perfect scores. It was the fifth game to receive ten out of ten from Edge. Critics praised the graphics, physics, story and gameplay. Maximum PC awarded Half-Life 2 11 on their rating scale which normally peaks at 10, calling it "the best game ever made". In the United States, Half-Life 2's PC version sold 680,000 copies and had earned $34.3 million by August 2006. It was the country's 17th best-selling PC game between January 2000 and August 2006. It received a "Platinum" sales award from the Entertainment and Leisure Software Publishers Association (ELSPA), indicating sales of at least 300,000 copies in the United Kingdom. Forbes reported on February 9, 2011, that it had sold 12 million copies worldwide. In a review of The Orange Box, IGN stated that although Half-Life 2 has already been released through other media, the game itself is still enjoyable on a console. They also noted that the physics of Half-Life 2 are impressive despite it being a console game. However, it was noted that the graphics on the Xbox 360 version of Half-Life 2 were not as impressive as when it was released on the PC. GameSpot identified framerate problems on PlayStation 3 version.
== Research == A 2023 systematic review of the literature identified only one study in which valproate was evaluated in the treatment of seizures in infants aged 1 to 36 months. In a randomized control trial, valproate alone was found to show poorer outcomes for infants than valproate plus levetiracetam in terms of reduction of seizures, freedom from seizures, daily living ability, quality of life, and cognitive abilities.
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.