Everything below concerns Semax. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-03-23. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
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.
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.
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.
Before the 1980s, cannabinoids were thought to produce their effects via nonspecific interaction with cell membranes, rather than specific membrane-bound receptors. The discovery of cannabinoid receptors in the 1980s resolved this debate. These receptors are common in animals, with two primary types, CB1 and CB2, and evidence suggests additional receptors may exist. The human brain has more cannabinoid receptors than any other G protein-coupled receptor (GPCR) type. The endocannabinoid system (ECS) regulates multiple functions, including movement, motor coordination, learning, memory, emotion, motivation, addictive-like behavior, and pain modulation.
EosFP was first discovered in 2005 during a large scale screen for PAFPs (photoactivatable fluorescent proteins) within the stony coral Lobophyllia hemprichii. It has since been successfully cloned in Escherichia coli and fusion constructs have been developed for use in human cells. Eos was named after the Greek goddess of dawn. Unlike the tetrameric fluorescent proteins derived from anthozoan coral, which can interfere with normal cellular function due to interactions between protein subunits, EosFP has been broken up into dimeric and monomeric variants through the introduction of single point mutations. These variants have been successful in the tracking of cellular components without disturbing function in the host cell and maintain the same photophysical properties as wild-type Eos. Since their discovery, monomeric Eos probes (mEos) have been shown to localize in the cytosol, plasma membrane, endosomes, prevacuolar vesicles, vacuoles, the endoplasmic reticulum, golgi bodies, peroxisomes, mitochondria, invaginations, filamentous actin and cortical microtubules. mEos fusion proteins allow for differential colour labelling in single cells, or groups of cells in developing organs. They can also be used for the understanding of spatial/ temporal interactions between organelles and vesicles. The two fluorescent forms of mEosFP (green and red) are compatible with CFP, GFP, YFP and RFP for multicolour labelling.
The periodic law may be represented in multiple ways, of which the standard periodic table is only one. Within 100 years of the appearance of Mendeleev's table in 1869, Edward G. Mazurs had collected an estimated 700 different published versions of the periodic table. Many forms retain the rectangular structure, including Charles Janet's left-step periodic table (pictured below), and the modernised form of Mendeleev's original 8-column layout that is still common in Russia. Other periodic table formats have been shaped much more exotically, such as spirals (Otto Theodor Benfey's pictured to the right), circles and triangles. Alternative periodic tables are often developed to highlight or emphasize chemical or physical properties of the elements that are not as apparent in traditional periodic tables, with different ones skewed more towards emphasizing chemistry or physics at either end. The many different forms of the periodic table have prompted the questions of whether there is an optimal or definitive form of the periodic table, and if so, what it might be. There are no current consensus answers to either question. Janet's left-step table is being increasingly discussed as a candidate for being the optimal or most fundamental form; Scerri has written in support of it, as it clarifies helium's nature as an s-block element, increases regularity by having all period lengths repeated, faithfully follows Madelung's rule by making each period correspond to one value of n + ℓ, and regularises atomic number triads and the first-row anomaly trend.
Sources: en.wikipedia.org
In 1943, the Nobel committee received a single nomination for the Nobel Prize in Physiology or Medicine for Fleming and Florey from the British biochemist Rudolph Peters. The secretary of the Nobel committee, Göran Liljestrand, made an assessment of Fleming and Florey in the same year, but little was known about penicillin in Sweden at the time, and he concluded that more information was required. The following year, there was one nomination for Fleming alone and one for Fleming, Florey and Chain. Liljestrand and Nanna Svartz, the professor of medicine at the Karolinska Institute, considered their work, and while both judged Fleming and Florey equally worthy of a Nobel Prize, the Nobel committee was divided, and decided to award the prize that year instead to Joseph Erlanger and Herbert S. Gasser "for their discoveries relating to the highly differentiated functions of single nerve fibres". There were a large number of nominations for Florey and Fleming or both in 1945, and one for Chain, from Liljestrand, who nominated all three. Liljestrand noted that thirteen of the first sixteen nominations that came in mentioned Fleming, but only three mentioned him alone. This time evaluations were made by Liljestrand, Sven Hellerström and Anders Kristenson, who endorsed all three. There were rumours that the committee would award the prize to Fleming alone, or half to Fleming and one-quarter each to Florey and Chain. Fulton and Dale lobbied for the award to be given to Florey.
The company is well known for its advertising catchphrase "Pizza! Pizza!", which was introduced in 1979. The phrase refers to two pizzas being offered for the comparable price of a single pizza from competitors. Initially, the pizzas were served in a single long package (a piece of corrugated cardboard in 2-by-1 proportions, with two pizzas placed side by side, then slid into a form-fitting paper sleeve that was folded and stapled closed). In 1988, they introduced a square deep-dish pizza called “Pan! Pan!”. Customers could purchase the “Pan! Pan!” pizzas as part of the 2-for-1 deal or mix and match with one pan pizza and one original round pizza. Little Caesars has since discarded the unwieldy packaging in favor of typical pizza boxes. For a time, in addition to pizza, the menu included hot dogs, chicken, sub sandwiches, shrimp, and fish. In the mid-1980s, Little Caesars opened several family entertainment centers in the Detroit and Chicago area with Little Caesars branding, initially being named Little Caesars Family Fun Pizzeria. Several of these locations were formerly Chuck E. Cheese's Pizza Time Theatre locations owned by Mike Ilitch. Little Caesars Family Fun Pizzeria would be rebranded into Caesarland by the mid-1990s, which featured play places similar to Discovery Zone. Caesarland would operate until 2011, when the last locations would close due to declining business. In 1997, the chain introduced shaker boards to advertise its "Hot-N-Ready Pizza", a large pepperoni pizza sold for $5.
== Response to cellular stress == In response to cellular stresses – such as infection, heat shock, or oxidative damage – heat shock proteins that identify misfolded or unfolded proteins and target them for proteasomal degradation are expressed. Both Hsp27 and Hsp90—chaperone proteins have been implicated in increasing the activity of the ubiquitin-proteasome system, though they are not direct participants in the process. Hsp70, on the other hand, binds exposed hydrophobic patches on the surface of misfolded proteins and recruits E3 ubiquitin ligases such as CHIP to tag the proteins for proteasomal degradation. The CHIP protein (carboxyl terminus of Hsp70-interacting protein) is itself regulated via inhibition of interactions between the E3 enzyme CHIP and its E2 binding partner. Similar mechanisms exist to promote the degradation of oxidatively damaged proteins via the proteasome system. In particular, proteasomes localized to the nucleus are regulated by PARP and actively degrade inappropriately oxidized histones. Oxidized proteins, which often form large amorphous aggregates in the cell, can be degraded directly by the 20S core particle without the 19S regulatory cap and do not require ATP hydrolysis or tagging with ubiquitin. However, high levels of oxidative damage increases the degree of cross-linking between protein fragments, rendering the aggregates resistant to proteolysis. Larger numbers and sizes of such highly oxidized aggregates are associated with aging. Dysregulation of the ubiquitin proteasome system may contribute to several neural diseases.
A second controversial aspect of the award was that eight months before Banting's and Best's paper, the Romanian physiologist Nicolae Paulescu had reported the discovery of a pancreas extract that he dubbed pancrein, which lowered blood glucose concentration. Banting and Best even cited him in their paper, but misinterpreted his findings, purportedly because of an error in translation from French. Best publicly apologized for that mistake many years later.
Sources: en.wikipedia.org
The suspensory ligaments of Cooper play an important role in the change in appearance of the breast that often accompanies the development of inflammatory carcinoma of the breast in which blockage of the local lymphatic ducts causes swelling of the breast. Because the skin remains tethered by the suspensory ligaments of Cooper, it takes on a dimpled appearance reminiscent of the peel of an orange (peau d'orange). Carcinomas can also decrease the length of Cooper's ligaments leading to a dimpling.
In 1959, Ivy began producing his own version of the drug under the name "Carcalon". On October 28, 1964, the Durovics, Ivy and the Krebiozen Research Foundation were indicted for introducing mislabeled drugs into interstate commerce in violation of the Food, Drug and Cosmetic Act. After a 9-month trial, the case ended with a hung jury and they were acquitted. Soon afterwards, Durovic was indicted for tax evasion and fled the United States.
=== NRPS revival: 2005–2017 === Shortly after the death of Spencer Dryden, a reconstituted line-up of the New Riders began touring in late 2005. It features David Nelson and Buddy Cage, alongside guitarist Michael Falzarano, bassist Ronnie Penque, and drummer Johnny Markowski. They have released a live album, Wanted: Live at Turkey Trot, and two studio albums, Where I Come From and 17 Pine Avenue. Allen Kemp died on June 25, 2009. John "Marmaduke" Dawson died in Mexico on July 21, 2009, at the age of 64. Pedal steel guitarist Buddy Cage died on February 5, 2020, at age 73. Prior to Cage's passing, the band had not performed for over two years and it has not been active since.
Sources: en.wikipedia.org
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.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.