Everything below concerns mass spectrometry. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-10. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
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.
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.
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.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
== Environmental concerns == A large Swedish study shows that it is broken down in wastewater plants and does not release into waterways. A Danish study shows that it biodegrades quickly, but that a risk of continuous leaching from boat paint may cause environmental toxicity.
Wojciech Jaruzelski, having been appointed First Secretary of the Polish United Workers' Party, introduces martial law, which drastically restricts normal life, in an attempt to crush the Solidarity trade union and the political opposition against communist rule.
=== Urban decay === Detroit has experienced significant urban decay—the process in which a previously flourishing city falls into disuse and disrepair, characterized commonly by empty plots of land, abandoned, decrepit, and often vandalized buildings, high unemployment rates, and high crime rates. Detroit has become one of the most infamous examples of such cities in the United States. Abandoned residential and commercial buildings are widespread; in 2014, 30% of residential buildings in the city were partially or fully vacant. The problem is so severe that the city has been likened to a ghost town. In the 1940s, Detroit was the fourth-largest city in the U.S. thanks in large part to the automobile industry. Vehicle manufacturers Ford, General Motors, and Chrysler had their factories there, which made the city a source of employment for many people. In the 1950s, the industry was no longer confined to Detroit; it began to spread out when vehicle manufacturers began to move their factories elsewhere, which led to the old factories being closed and abandoned, and eventually, many of them were vandalized. This was a side effect of automation and globalization. While improvements have been made, blight remains specifically in predominantly African American neighborhoods. A significant percentage of housing parcels in the city are vacant, with abandoned lots making up more than half of total residential lots in large portions of the city. With at least 70,000 abandoned buildings, 31,000 empty houses, and 90,000 vacant lots, Detroit has become notorious for its urban blight.
Sources: en.wikipedia.org
== Synthesis == Because ELPs are protein-based biopolymers, synthesis involves manipulation of genes to continually express the monomeric repeat unit. Various techniques have been employed in the production of ELPs of various sizes, including unidirectional ligation or concatemerization, overlap extension polymerase chain reaction (OEPCR), and recursive directional ligation (RDL). Also, ELPs can be experimentally modified through conjugation with other polymers or through SpyTag/SpyCatcher reaction, allowing for the synthesis of copolymers with unique morphology.
The term nanoporous materials contain subsets of microporous and mesoporous materials. Microporous materials are porous materials with a mean pore size smaller than 2 nm, while mesoporous materials are those with pores sizes in the region 2–50 nm. Microporous materials exhibit pore sizes with comparable length-scale to small molecules. For this reason such materials may serve valuable applications including separation membranes. Mesoporous materials are interesting towards applications that require high specific surface areas, while enabling penetration for molecules that may be too large to enter the pores of a microporous material. In some sources, nanoporous materials and nanofoam are sometimes considered nanostructures but not nanomaterials because only the voids and not the materials themselves are nanoscale. Although the ISO definition only considers round nano-objects to be nanoparticles, other sources use the term nanoparticle for all shapes.
Sherman (1930–2008), 12 US patents John Sherwood (died 2020), British physical chemist Nevil Vincent Sidgwick (1873–1952), English theoretical chemist, known for work in valency Osamu Shimomura (1928–2018), 2008 Nobel Prize in Chemistry Hideki Shirakawa (1936–2026), 2000 Nobel Prize in Chemistry Alexander Shulgin (1925–2014), pioneer researcher in Psychopharmacology and Entheogens Salimuzzaman Siddiqui (1897–1994), Pakistani chemist, pioneer in natural products chemistry Oktay Sinanoglu (1935–2015), Turkish chemist Joseph H. Simons (1897–1983), U.S. chemist, discoverer of fluorocarbons, used in gaseous diffusion of Uranium for Manhattan project Jens Christian Skou (1918–2018), 1997 Nobel Prize in Chemistry Richard Smalley (1943–2005), 1996 Nobel Prize in Chemistry Michael Smith (1932–2000), 1993 Nobel Prize in Chemistry Ascanio Sobrero (1812–1888), Italian chemist, discoverer of nitroglycerin Frederick Soddy (1877–1956), British chemist, 1921 Nobel Prize in Chemistry Susan Solomon (born 1956), American atmospheric chemist Ernest Solvay (1838–1922), Belgian chemist and industrialist S.P.L. Sørensen (1868–1939), Danish chemist Gabor A.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.