TKPRPGP raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-05-29 and is reviewed periodically as new material appears.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
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.
| 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 |
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.
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.
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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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.
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.
=== Kinetically frozen micelles === When block copolymer micelles do not display the characteristic relaxation processes of surfactant micelles, these are called kinetically frozen micelles. These can be achieved in two ways: when the unimers forming the micelles are not soluble in the solvent of the micelle solution, or if the core forming blocks are glassy at the temperature in which the micelles are found. Kinetically frozen micelles are formed when either of these conditions is met. A special example in which both of these conditions are valid is that of polystyrene-b-poly(ethylene oxide). This block copolymer is characterized by the high hydrophobicity of the core forming block, PS, which causes the unimers to be insoluble in water. Moreover, PS has a high glass transition temperature which is, depending on the molecular weight, higher than room temperature. Thanks to these two characteristics, a water solution of PS-PEO micelles of sufficiently high molecular weight can be considered kinetically frozen. This means that none of the relaxation processes, which would drive the micelle solution towards thermodynamic equilibrium, are possible. Pioneering work on these micelles was done by Adi Eisenberg. It was also shown how the lack of relaxation processes allowed great freedom in the possible morphologies formed. Moreover, the stability against dilution and vast range of morphologies of kinetically frozen micelles make them particularly interesting, for example, for the development of long circulating drug delivery nanoparticles.
== Keratin removal == Keratin that is present in the hair, scales and in the epidermis of the skin is hydrolyzed in the presence of alkali (at pH values greater than 11.5). The disulfide bridges found in keratin protein are cleaved but can be reformed. Long periods of liming will result in hair removal. The main removal of keratin is performed during the unhairing operation. In traditional processing, liming and unhairing were indivisible and took place at the same time. During modern liming methods, and in particular the processing of sheepskins, the hair is removed first and then limed in a liming drum. In hair-save technology, the hides are unhaired first and then limed for a further 12–18 hours.
The ion source is the part of the mass spectrometer that transforms the sample from the sample inlet into a stream of ions. There are many techniques with various dimensions for tradeoffs between different choices of ion sources, in terms of monetary cost, accuracy, precision, compatibility with other stages of spectroscopy, ease of use, etc. For example, electron ionization (EI) gives a high degree of fragmentation, yielding highly detailed mass spectra which when skilfully analysed can provide important information for structural elucidation/characterisation and facilitate identification of unknown compounds by comparison to mass spectral libraries obtained under identical operating conditions. However, EI is not suitable for coupling to HPLC, i.e. LC-MS, since at atmospheric pressure, the filaments used to generate electrons burn out rapidly. Thus EI is coupled predominantly with GC, i.e. GC-MS, where the entire system is under high vacuum. Two techniques often used with liquid and solid biological samples include electrospray ionization (invented by John Fenn) and matrix-assisted laser desorption/ionization (MALDI, initially developed as a similar technique Soft Laser Desorption) by K. Tanaka for which a Nobel Prize was awarded and as MALDI by M. Karas and F. Hillenkamp).
Ma Bo mentioned hardtack as being a staple food of Chinese hard-labor workers in Inner Mongolia, during the Cultural Revolution. Hardtack was a staple of military servicemen in Japan and South Korea well into the late 20th century. It is known as Kanpan (乾パン) in Japan and geonbbang (geonppang, 건빵) in South Korea, meaning 'dry bread', and is still sold as a fairly popular snack food in both countries. (Canned kanpan is also distributed in Japan as emergency rations in case of earthquake, flood, or other disaster.) A harder hardtack than Kanpan, called Katapan (堅パン), is historically popular in Kitakyushu, Fukuoka, Japan as one of its regional specialty foods. In Korea, geonppang (hardtacks) mixed with byulsatang (star candy) as a medley is considered a popular snack.
Annie-Laurie Ala von Auersperg (born 1958), co-founder of the National Center for Victims of Crime, who married financier Ralph H. Isham, son of diplomat Heyward Isham. Alexander Georg von Auersperg (born 1959), co-founder of the National Center for Victims of Crime, who married investment banker Nancy Louise Weinberg. The Auerspergs were divorced in 1965. At that time, Sunny's net worth was over $75 million. Alfred Auersperg died in 1992 after lingering in an irreversible coma for nine years following a 1983 car accident in Austria. On June 6, 1966, Sunny married Claus von Bülow, a former aide to oilman J. P. Getty, at the Brick Presbyterian Church in New York City. His maternal grandfather, whose surname he took, was Frits Toxwerdt von Bülow, Justice Minister of Denmark in the government of Klaus Berntsen (1910–1913) and also came from a noble background. Together, they had a daughter:
Sources: en.wikipedia.org
ICT appears to be vanishing as a result of greater genetic diversity within the affected populations in conjunction with educational programs to ensure that tinned cooking utensils are used instead of copper pots and pans being directly exposed to cooked foods. The preponderance of cases of early childhood cirrhosis identified in Germany over a period of 10 years were not associated with either external sources of copper or with elevated hepatic metal concentrations Only occasional spontaneous cases of ICT arise today.
=== Opposition to COVID-19 vaccine requirements (2021) === In October 2021, the In-N-Out location in San Francisco was ordered closed by the San Francisco Department of Public Health (SFDPH), for failure to enforce the public health order requiring that all dine-in patrons of restaurants present proof that they are fully vaccinated for COVID-19. The location had posted signage warning of the mandate, but the SFDPH received complaints that it was not actually enforced. The company's chief legal officer Arnie Wensinger stated that the company "fiercely disagree[s] with any government dictate that forces a private company to discriminate against customers who choose to patronize their business". The location was allowed to re-open for takeout service only until it demonstrates "an adequate process and procedure for complying with the health order". Later that month, after an In-N-Out location in Contra Costa County was similarly ordered closed by public health for not complying with its vaccine mandate, all In-N-Out locations in the region closed their dining rooms and began operating with takeout service only. The locations attracted anti-mandate demonstrations in support of the company.
== Biotechnology == The 7kDa proteins are valuable tools in biotechnology due to their ability to bind any dsDNA. When grafted onto a DNA polymerase, it greatly enhances the processivity of the enzyme by helping it stay bound to the DNA. Using such a modified enzyme allows a polymerase chain reaction to copy much longer pieces of DNA at a faster rate. Such fusion polymerases are sold under various tradenames under premium prices since 2014, but they can also be made and purified in a lab. (The commercial versions include additional mutations for performance.) The 7kDa protein scaffold is also a good starting point for artificial affinity proteins (affitins) that can be used to bind any molecule of interest. Techniques such as phage display are used to screen a wide variety of mutants and select for the good binders. Compared to antibodies, they are much smaller and much stabler.
=== Public employee pensions === Pritzker refused to take on the City of Chicago's pension liabilities, believing that would jeopardize Illinois's credit rating. Moody's raised it to one level above "junk" after Illinois passed a balanced budget in 2019. But Pritzker did not reject the possibility of allowing Chicago to pool its pension funds with other parts of the state, and created a task force to find ways to tackle municipalities' ballooning pension debts. Pension funds in Illinois are collectively funded at only 47.8%.
Sources: en.wikipedia.org
== Additional Union Carbide actions == The corporation denied the claim that valves on the tank were malfunctioning and claimed that documented evidence gathered after the accident showed the valve closest to the plant's water-washing operation was closed and leak-tight. Furthermore, process safety systems had prevented water from entering the tank by accident. Carbide states that all safety concerns identified in 1982 were allayed before 1984 and had nothing to do with the accident. The company admitted that safety systems in place would not have been able to prevent a chemical reaction of such magnitude from causing a leak. According to Carbide, "in designing the plant's safety systems, a chemical reaction of this magnitude was not factored in" because "the tank's gas storage system was designed to automatically prevent such a large amount of water from being inadvertently introduced into the system" and "process safety systems—in place and operational—would have prevented water from entering the tank by accident". Instead, they claim that "employee sabotage—not faulty design or operation—was the cause of the tragedy". Tactical response The company stresses the immediate action taken after the disaster and its continued commitment to helping the victims. On 4 December, the day following the leak, Union Carbide sent material aid and several international medical experts to assist the medical facilities in Bhopal.
=== β-α-β motif === Due to the chirality of their component amino acids, all strands exhibit right-handed twist evident in most higher-order β-sheet structures. In particular, the linking loop between two parallel strands almost always has a right-handed crossover chirality, which is strongly favored by the inherent twist of the sheet. This linking loop frequently contains a helical region, in which case it is called a β-α-β motif. A closely related motif called a β-α-β-α motif forms the basic component of the most commonly observed protein tertiary structure, the TIM barrel.
In the most expensive political campaign in Vermont's history, Sanders defeated businessman Rich Tarrant by an almost 2-to-1 margin. Many national media outlets projected him as the winner just after the polls closed, before any returns came in.
==== Grafting to ==== Grafting to approach which is the most common and straightforward methodology refers to directly attaching the synthetic polymers to the target protein. This technique can be engineered for site-specific or random conjugation and, when compared to other conjugation methods, provides simple and thorough characterization of polymer before conjugation. And when using this method, the protein remains unaffected by polymerization methods.
{\displaystyle \log P_{\text{oct/wat}}=\log _{10}\left({\frac {{\big [}{\text{solute}}{\big ]}_{\text{octanol}}^{\text{un-ionized}}}{{\big [}{\text{solute}}{\big ]}_{\text{water}}^{\text{un-ionized}}}}\right).}
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.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.