lyophilized powder comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-17. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
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.
== Function == This gene encodes a subunit of the elongation factor-1 complex, which is responsible for the enzymatic delivery of aminoacyl tRNAs to the ribosome. This subunit contains an N-terminal glutathione transferase domain, which may be involved in regulating the assembly of multisubunit complexes containing this elongation factor and aminoacyl-tRNA synthetases.
...Had Sony stuck with the original plan of a scaled-down superhero franchise, one that really was rooted in romantic drama, they would have at least stuck out in a crowded field of superhero franchises. When every superhero film is now going bigger, Amazing Spider-Man could have distinguished itself by going small and intimate." This would have saved Sony "a boatload of money", and potentially reversed the film's relative financial failure.
Although PI3K is the major mode of Akt activation, other tyrosine or serine/threonine kinases have been shown to activate Akt directly, in response to growth factors, inflammation or DNA damage. These can function even when PI3K activity is inhibited. Other studies have shown Akt can be activated in response to heat shock or increases in cellular Ca2+ concentration, via Ca2+/Calmodulin-dependent protein kinase kinase (CAMKK).
A significant amount of zirconium is formed by the fission process; some of this consists of short-lived radionuclides (95Zr and 97Zr which decay to molybdenum), while almost 10% of the fission products mixture after years of decay consists of five stable or nearly stable isotopes of zirconium plus 93Zr with a halflife of 1.53 million years which is one of the 7 major long-lived fission products. Zirconium is commonly used in cladding of fuel rods due to its low neutron cross section. However, a small share of this zirconium does capture neutrons and contributes to the overall inventory of radioactive zirconium isotopes. Zircalloy cladding is not commonly reused and neither is fission product zirconium, which could be used in cladding as its relatively weak radioactivity would be of no major concern inside a nuclear reactor. Despite its high yield and long live, Zr-93 is generally not deemed to be of major concern as it is not chemically mobile and emits little radiation. In PUREX plants the zirconium (regardless of source or isotope) sometimes forms a third phase which can be a disturbance in the plant. The third phase is the term in solvent extraction given to a third layer (such as foam and/or emulsion) which forms from the two layers in the solvent extraction process. The zirconium forms the third phase by forming small particles which stabilise the emulsion which is the third phase. Zirconium-90 mostly forms by successive beta decays out of strontium-90.
1 May A new brain-reading method for "semantic decoding" is demonstrated. The non-invasive system, based on 16 hours of fMRI data per participant and a transformer, is able to translate a person's neural activity into a continuous stream of text. News outlets report the first study (6 Feb) modelling contemporary detectability of human civilization from afar which suggests overall radio-leakage from mobile towers would still be too weak to be detectable with humanity's next-generation radio telescopes from three of Earth's current closest nearby star-systems. Radar systems are not yet included in their model, while radar emissions during – and possibly since – the Cold War are thought to be the first most detectable cue by which hypothetical extraterrestrials could detect humanity. The second study, after one from early 2022 with similar results, about EEG data of dying humans finds a surge of gamma waves and increased functional connectivities in two of four patients. It provides data and analysis about the brain process of dying (terminal loss of sentience and life) and near-death experiences. 2 May A new AI algorithm developed by Baidu is shown to boost the antibody response of COVID-19 mRNA vaccines by 128 times. A single-molecule valve is demonstrated, a breakthrough in nanoscale control of fluids. Scientists report economic factors of neurology or mental health and cognition during child development: association of low income with brain structure and hippocampal volume, stronger associations in U.S.
Sources: en.wikipedia.org
=== Since 2014 === In early 2014, Marcel H. Van Herpen, director of the Cicero Foundation, published the book Putin's Wars: The Rise of Russia's New Imperialism that offered the first systematic analysis of the war in the wider historical context. Van Herpen suggested that although the official Russian narrative (that the war started with a Georgian "surprise" attack on Tskhinvali) became widely accepted, this was not true since the war's history actually began in 2000 (although Russia had planned to annex Abkhazia already in the 1990s), and 7–12 August 2008 was the third phase of the war. Illegal entry of the troops from Russia into South Ossetia before the Georgian military operation began on 7 August, was a casus belli. Because of the Russian propaganda, the victim (Georgia) became the aggressor. Van Herpen finished writing the book in late 2013, and predicted "if Ukraine were to opt for deeper integration into the European Union, a Georgia scenario could not be excluded, in which the Kremlin could provoke riots in Eastern Ukraine or the Crimea, where many Russian passport holders live". In April 2014, Jeffrey Mankoff argued that Russia and South Ossetia provoked the Georgian response. Mankoff also noted that while Russia used the justification of the defense of minorities in Georgia for military intervention, Russia never intervened in Central Asia to protect ethnic Russians there.
=== Infection === E. floccosum causes superficial diseases such as tinea pedis (athlete's foot) and tinea cruris, and less commonly tinea corporis and onychomycosis. Similar to other fungal dermatophytes, E. floccosum can invade keratinized tissues including skin and nails. A recent clinical case has also demonstrated its capacity of infecting eyes, causing keratitis. It does not perforate hair or hair follicles. This anthropophilic dermatophyte preferentially infects humans and rarely infects animals, thus lab animal experiments are found to be unsuccessful. E. floccosum is more infective than most dermatophytes. Chronic infections are rare, therefore maintenance of the species relies on rapid transmission between hosts. The infection typically stays within the nonliving conidified layer of host epidermis, since the fungus cannot pierce through living tissues of individuals with normal immunity. However, it has been found to cause invasive infections in immunocompromised patients, demonstrating severe onychomycosis, skin lesions, and subcutaneous nodules.
== Principle == The assay principle of peptide microarrays is similar to an ELISA protocol. The peptides (up to tens of thousands in several copies) are linked to the surface of a glass chip typically the size and shape of a microscope slide. This peptide chip can directly be incubated with a variety of different biological samples like purified enzymes or antibodies, patient or animal sera, cell lysates and then be detected through a label-dependent fashion, for example, by a primary antibody that targets the bound protein or modified substrates. After several washing steps a secondary antibody with the needed specificity (e.g. anti IgG human/mouse or anti phosphotyrosine or anti myc) is applied. Usually, the secondary antibody is tagged by a fluorescence label that can be detected by a fluorescence scanner. Other label-dependent detection methods includes chemiluminescence, colorimetric or autoradiography. Label-dependent assays are rapid and convenient to perform, but risk giving rise to false positive and negative results. More recently, label-free detection including surface plasmon resonance (SPR) spectroscopy, mass spectrometry (MS) and many other optical biosensors have been employed to measuring a broad range of enzyme activities. Peptide microarrays show several advantages over protein microarrays:
PCP has multiple routes of administration. Most commonly, the powder form of the drug is snorted. PCP can also be orally ingested, injected subcutaneously or intravenously, or smoked laced with marijuana or cigarettes.
Treosulfan, sold under the brand name Trecondi among others, is an alkylating medication given to people before they have a bone marrow transplant from a donor known as allogeneic hematopoietic stem cell transplantation. It is used as a 'conditioning' treatment to clear the bone marrow and make room for the transplanted bone marrow cells, which can then produce healthy blood cells. It is used together with another medicine called fludarabine in adults and children from one month of age with blood cancers as well as in adults with other severe disorders requiring a bone marrow transplant. It belongs to the family of drugs called alkylating agents. In the body, treosulfan is converted into other compounds called epoxides which kill cells, especially cells that develop rapidly such as bone marrow cells, by attaching to their DNA while they are dividing. DNA cross-linking is considered a primary mechanism underlying the pharmacological action of treosulfan, and epoxides formed from treosulfan may cross-link DNA via at least two chemical pathways. Preclinical studies in animal models have shown that treosulfan is widely distributed to the liver, lungs, bone marrow, and skeletal muscle, with tissue-to-plasma ratios of 0.96, 0.82, 0.82, and 0.77, respectively. Lower biodistribution was observed in the brain and the aqueous humor of the eye (both 0.10). In juvenile rats with an immature blood–brain barrier, brain exposure was higher (0.15) than in young adult rats.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.