This is a working overview of amino acid sequence, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-02-20. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
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.
== See also == Dipeptidyl peptidase-4 Gastric inhibitory polypeptide GLP-1 receptor agonists—albiglutide, dulaglutide, exenatide, liraglutide, lixisenatide, tirzepatide, and semaglutide, the last of which is marketed under the brands Ozempic, Rybelsus, and Wegovy. Glucagon Glucagon-like peptide-1 receptor Glucagon-like peptide-2 Type 2 diabetes
== Endogenous opioid peptides == There are three well-characterized families of opioid peptides produced by the body: enkephalins, β-endorphin, and dynorphins. The met-enkephalin peptide sequence is coded for by the enkephalin gene; the leu-enkephalin peptide sequence is coded for by both the enkephalin gene and the dynorphin gene. The proopiomelanocortin gene (POMC) also contains the met-enkephalin sequence on the N-terminus of β-endorphin, but the endorphin peptide is not processed into enkephalin.
Cannabis users demonstrated increased activity in task-related brain regions, consistent with reduced processing efficiency. A reduced quality of life is associated with heavy cannabis use, although the relationship is inconsistent and weaker than for tobacco and other substances. The direction of cause and effect, however, is unclear. The long-term effects of cannabis are not clear. There are concerns surrounding memory and cognition problems, risk of addiction, and the risk of schizophrenia in young people.
Sources: en.wikipedia.org
The matrix can be used to tune the instrument to ionize the sample in different ways. As mentioned above, acid-base like reactions are often utilized to ionize the sample, however, molecules with conjugated pi systems, such as naphthalene like compounds, can also serve as an electron acceptor and thus a matrix for MALDI/TOF. This is particularly useful in studying molecules that also possess conjugated pi systems. The most widely used application for these matrices is studying porphyrin-like compounds such as chlorophyll. These matrices have been shown to have better ionization patterns that do not result in odd fragmentation patterns or complete loss of side chains. It has also been suggested that conjugated porphyrin like molecules can serve as a matrix and cleave themselves eliminating the need for a separate matrix compound.
Legendary sniper Thomas Beckett and his son, Special Ops sniper Brandon Beckett, are on the run from the CIA, Russian mercenaries, and a Yakuza-trained assassin with sniper skills that rival both legendary sharp shooters.
=== Flagship facility === UPMC Presbyterian Shadyside is UPMC's primary flagship medical entity and represents the core of UPMC's academic, teaching, trauma, specialty and research-related facilities, serving as the system's primary academic hub and Pennsylvania's largest inpatient acute care hospital. UPMC Presbyterian Shadyside includes UPMC Presbyterian hospital and the physically conjoined UPMC Eye & Ear and UPMC Montefiore hospitals as well as the UPMC Western Psychiatric Hospital that also serves as the University of Pittsburgh's Thomas Detre Hall. These facilities are all located on the western side of the University of Pittsburgh's main campus in the Oakland neighborhood of Pittsburgh. The hospitals are also physically connected to the University of Pittsburgh School of Medicine's Scaife Hall, the University of Pittsburgh School of Nursing's Victoria Hall, Falk Clinic, three of the university's biomedical science towers, and the university's Lothrop Hall dormitory, all of which are surrounded by a variety of other academic facilities. UPMC Presbyterian Shadyside also encompasses the UPMC Shadyside hospital campus which includes the University of Pittsburgh Cancer Institute in the UPMC Hillman Cancer Center which are located near the university's Centre Plaza Apartments student housing. The UPMC Shadyside facilities are located in the adjacent neighborhood of Shadyside approximately 1.5 miles (2.4 km) from the Oakland-based hospitals and are connected by regular shuttle service.
Sources: en.wikipedia.org
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.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.