Everything below concerns peptidase. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
| 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 |
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
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.
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.
On March 13, 2019, three years after voters narrowly rejected its repeal in the 2016 California Proposition 62, Newsom declared a moratorium on the state's death penalty, preventing any execution in the state as long as he remained governor. The move also led to the withdrawal of the state's current lethal injection protocol and the execution chamber's closure at San Quentin State Prison. In a CBS This Morning interview, Newsom said that the death penalty is "a racist system ... that is perpetuating inequality. It's a system that I cannot in good conscience support." The moratorium granted a temporary reprieve for all 737 inmates on California's death row, then the largest death row in the Western Hemisphere. In January 2022, Newsom directed the state to begin dismantling its death row in San Quentin, to be transformed into a "space for rehabilitation programs", as all the condemned inmates were moving to other prisons that have maximum security facilities. The state's voters upheld capital punishment in 2012 and 2016, agreeing when they did so in 2016 to move the condemned to other prisons. While a 2021 poll by the UC Berkeley Institute of Governmental Studies and co-sponsored by the Los Angeles Times suggested declining support for capital punishment among California's voters, Republican opponents criticized Newsom's moves to halt capital punishment in California as defiance of the will of voters, and capital punishment advocates said they denied closure to murder victims' families.
=== Development of pretargeted imaging === To bypass the problem associated with the prolonged circulation time of radiolabelled antibodies, in the mid-1980s a strategy called pretargeted radioimmunotherapy was developed. In short, this approach contained two important steps: 1. administration of a macromolecular targeting vector (usually antibody-based), and 2. a small radiolabelled molecule, which interacts with the targeting vector. Most importantly the small radiolabelled molecule gets injected after a predetermined lag period after which the macromolecule has had enough time to bind to its target and the residual unbound macromolecule to be cleared out of the system. To ensure sufficient interaction between the two components, suitable modifications with complementary species are required (like bioorthogonal modifications). Pretargeting strategies can lead to an improved imaging contrast, as it combines the high target specificity and affinity of an antibody with the fast pharmacokinetic properties of a small molecule. The concept of pretargeting, although existing for several decades already, was limited to a few distinct classes. Developing chemical reactions that proceed quickly within living systems, without interacting with the large variety of existing functional groups, used to be an inherent difficulty. However, there have been several advancements in this area over the past few years.
Mendelevium was the ninth transuranic element to be synthesized. It was first synthesized by Albert Ghiorso, Glenn T. Seaborg, Gregory Robert Choppin, Bernard G. Harvey, and team leader Stanley G. Thompson in early 1955 at the University of California, Berkeley. The team produced 256Md (half-life 77.7 minutes) when they bombarded an 253Es target consisting of only a billion (109) einsteinium atoms with alpha particles (helium nuclei) in the Berkeley Radiation Laboratory's 60-inch cyclotron, thus increasing the target's atomic number by two. 256Md thus became the first isotope of any element to be synthesized one atom at a time. In total, seventeen mendelevium atoms were detected. This discovery was part of a program, begun in 1952, that irradiated plutonium with neutrons to transmute it into heavier actinides. This method was necessary because of a lack of known beta decaying isotopes of fermium that might allow production by neutron capture; it is now known that such production is impossible at any possible reactor flux due to the very short half-life to spontaneous fission of 258Fm and subsequent isotopes, which still do not beta decay - the fermium gap that, as far as we know, sets a hard limit to the success of neutron capture processes.
Sources: en.wikipedia.org
In a December 2022 editorial published just before being elected US House speaker, Kevin McCarthy wrote that "China and the US are locked in a cold war". The op-ed also announced the creation of the United States House Select Committee on Strategic Competition between the United States and the Chinese Communist Party. In early 2023, Jorge Heine, former Chilean ambassador to China and professor of international relations at Boston University, said the looming new Cold War between the US and China has become apparent to "a growing consensus", and described the new Cold War as "more alike than [it is] different" from the one fought between the US and Soviet Union, and saying the presence of "ideological-military overtones is now widely accepted". After the 2023 Chinese balloon incident, Evan Osnos wrote for The New Yorker "The blocs in this new cold war are hardening." Shortly after the Russian invasion of Ukraine, Germany had "announced a 'turning point'" in its relationship with Russia. The 2022 Madrid NATO summit hosted leaders from South Korea, Australia, Japan, and New Zealand, who all "voiced unprecedented concern about China's ambitions". The Biden administration strengthened the U.S.'s military ties and activities with Australia, Japan, India, and the Philippines, to "bolster its ability to defend Taiwan". In the October 2024 article for the TomDispatch blog, a history professor Alfred W. McCoy wrote that, despite rising renewed tensions between China and the US, the Asia-Pacific allies of the US would be likely losers.
Either directly or indirectly, wine yeast can be a culprit behind a wide variety of wine faults. These can include the presence of "off flavors" and aromas that can be the by-product of some "wild yeast" fermentation such as those by species within the genera of Kloeckera and Candida. Even the common wine yeast Saccharomyces cerevisiae can be behind some wine faults with some strains of the yeast known to produce higher than ideal levels of acetic acid, acetaldehyde and volatile sulfur compounds such as thiols. Also any yeast can have a low tolerance to nutritional deficiencies, temperature fluctuation or extremes and excessive or low sugar levels that may lead to a stuck fermentation. In the presence of oxygen several species of Candida and Pichia can create a film surface on top of the wine in the tank of barrel. Allowed to go unchecked, these yeasts can rapidly deplete the available free sulfur compounds that keeps a wine protected from oxidation and other microbial attack. The presence of these yeasts is often identified by elevated levels of volatile acidity, particularly acetic acid. Some strains of Pichia will metabolize acetic acid (as well as ethyl acetate and isoamyl acetate that may also be produced) with the side-effect of substantially decreasing the titratable acidity and shifting the pH of wine upwards to levels that make the wine prone to attack by other spoilage microbes. Commonly called "film yeast", these yeasts are distinguished from the flor sherry yeast that are usually welcomed by winemakers in producing the delicate fino-style wines.
Radio-controlled models – a popular hobby is playing with radio-controlled model boats, cars, airplanes, and helicopters (quadcopters) which are controlled by radio signals from a handheld console with a joystick. Most recent transmitters use the 2.4 GHz ISM band with multiple control channels modulated with PWM, PCM or FSK. Wireless doorbell – A residential doorbell that uses wireless technology to eliminate the need to run wires through the building walls. It consists of a doorbell button beside the door containing a small battery powered transmitter. When the doorbell is pressed it sends a signal to a receiver inside the house with a speaker that sounds chimes to indicate someone is at the door. They usually use the 2.4 GHz ISM band. The frequency channel used can usually be changed by the owner in case another nearby doorbell is using the same channel.
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.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.