Peptide mapping 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 2026-06-25 and is reviewed periodically as new material appears.
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.
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
| 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 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.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
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.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Folding is a spontaneous process that is mainly guided by hydrophobic interactions, formation of intramolecular hydrogen bonds, van der Waals forces, and it is opposed by conformational entropy. The folding time scale of an isolated protein depends on its size, contact order, and circuit topology. Inside cells, the process of folding often begins co-translationally, so that the N-terminus of the protein begins to fold while the C-terminal portion of the protein is still being synthesized by the ribosome; however, a protein molecule may fold spontaneously during or after biosynthesis. While these macromolecules may be regarded as "folding themselves", the process also depends on the solvent (water or lipid bilayer), the concentration of salts, the pH, the temperature, the possible presence of cofactors and of molecular chaperones. Proteins will have limitations on their folding abilities by the restricted bending angles or conformations that are possible. These allowable angles of protein folding are described with a two-dimensional plot known as the Ramachandran plot, depicted with psi and phi angles of allowable rotation.
In 1927, a Southland Ice Company employee named John Jefferson Green began selling ice, eggs, milk, and bread from 16 ice house storefronts in Dallas, with permission from one of Southland's founding directors, Joe C. Thompson Sr. Although small grocery stores and general merchandisers were available, Thompson theorized that selling products like bread and milk in convenience stores would reduce the need for customers to travel long distances for basic items. Thompson eventually bought the Southland Ice Company and turned it into the Southland Corporation, which oversaw several locations in the Dallas area. In 1928, a manager named Jenna Lira brought a totem pole from Alaska and placed it in front of her store. The pole served as a marketing tool for the company, as it attracted a great deal of attention. Soon, executives added totem poles in front of every store and eventually adopted an Alaska Native-inspired theme. Later on, the stores began operating under the name "Tote'm Stores". That same year, the company began constructing filling stations at some of its Dallas locations as an experiment. Joe Thompson introduced staff training to ensure that customers would receive the same quality and service in every store. Additionally, Southland introduced a uniform for its ice station service boys. In 1931, the Great Depression affected the company, sending it toward bankruptcy. Nevertheless, the company continued its operations through re-organization and receivership. A Dallas banker, W. W.
Under the Military Law of September 1925, the Soviet Armed Forces consisted of the Land Forces, the Red Army Air Force, the Navy, Joint State Political Directorate (OGPU) and the Internal Troops. The OGPU later became independent and in 1934 joined the NKVD secret police, and so its internal troops were under the joint leadership of the defence and internal commissariats. After World War II, Strategic Missile Forces (1959), Air Defense Forces (1948) and National Civil Defense Forces (1970) were formed, which ranked first, third, and sixth in the official Soviet system of importance (ground forces were second, Air Force fourth, and Navy fifth). The army had the greatest political influence. In 1989, there served two million soldiers divided between 150 motorized and 52 tank divisions. Until the early 1960s, the Soviet navy was a rather small military branch, but after the Cuban Missile Crisis, under the leadership of Sergei Gorshkov, it expanded significantly. It became known for its submarine fleet. In 1989, there served 500,000 men. The Soviet Air Force focused on a fleet of strategic bombers and during war situation was to eradicate enemy infrastructure and nuclear capacity. The air force also had a number of fighters and tactical bombers to support the army in the war. Strategic missile forces had more than 1,400 intercontinental ballistic missiles (ICBMs), deployed between 28 bases and 300 command centres. After 1945, the Soviet Ground Forces suppressed several uprisings in East Europe and was involved in many other operations abroad.
==== Syrian Arab Republics ==== In 2013, Damascus University instituted a Master's program in Medical Physics, which has significantly contributed to the training of numerous medical physicists across various university and local hospitals, as well as several universities within the Syrian Arab Republic. This program has facilitated the dissemination of knowledge through the publication of several external research articles addressing the role of medical physicists in oncology. Furthermore, it has resulted in the production of multiple academic textbooks in the field of medical physics.
Sources: en.wikipedia.org
the sensitivity of the product to temperatures (high and low) and to time at temperatures the specific distribution system being used: the expected (and worst case) time and temperatures regulatory requirements the specific combination of packaging components and materials being used In specifying an insulated shipping container, the two primary characteristics of the material are its thermal conductivity or R-value, and its thickness. These two attributes will help determine the resistance to heat transfer from the ambient environment into the payload space. The coolant material load temperature, quantity, latent heat, and sensible heat will help determine the amount of heat the parcel can absorb while maintaining the desired control temperature. Combining the attributes from the insulator and coolant will allow analysis of expected duration of the insulated shipping container system. Testing of multi-component systems is needed.
== Lord's Resistance Army insurgency == The United States had been involved clandestinely in the Lord's Resistance Army insurgency since at least 2008; President Barack Obama deployed forces here in October 2011, the deployment is known as Operation Observant Compass. In March 2017, NBC News reported that Green Berets have been ordered to "apprehend or remove" Joseph Kony, one of the world's most notorious warlords from the battlefield, along with his top commanders. With about 80 military personnel and several dozen support personnel they were tasked with finding around 150 LRA fighters in an area of operations the size of California; carrying out missions (specifically patrols) in the Central African Republic, Democratic Republic of the Congo, South Sudan and Uganda. The cooperation between U.S. special forces and the UPDF has led to notable successes: In January 2015, Green Berets were present after Dominic Ongwen turned himself in to authorities; previously in October 2012, an Invisible Children, Inc. program that encourages defections from the group and the rehabilitation of former fighters and escaped abductees resulted in notable defections, including several bodyguards; the LRA's "chief intelligence officer" who walked for four days from Sudan into CAR, was handed over to the UPDF with U.S. special forces present. LtCol Matt Maybouer, the commander of the operation said that "U.S. soldiers are not engaged in direct combat;" Green Beret teams conducting patrols carryout zone reconnaissance: a coordinated search for recent LRA activity.
== Fingers == The fingertips have many nerves and are responsive to very light touches, like the brushing of a tongue, light fingernail scratching or teeth stroking. The sides of the fingers are somewhat less sensitive and more ticklish. Both light and firmer touches work well at the junction of the fingers. Human fingertips are the second-most sensitive parts of the body, after the tongue.
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.
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.