Selank 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 2025-10-07 and is reviewed periodically as new material appears.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
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.
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== Design == Brentuximab vedotin consists of the chimeric monoclonal antibody brentuximab (cAC10, which targets the cell-membrane protein CD30) linked with maleimide attachment groups, cathepsin-cleavable linkers (valine-citrulline), and para-aminobenzylcarbamate spacers to three to five units of the antimitotic agent monomethyl auristatin E (MMAE, reflected by the 'vedotin' in the drug's name). The peptide-based linker bonds the antibody to the cytotoxic compound in a stable manner so the drug is not easily released from the antibody under physiologic conditions to help prevent toxicity to healthy cells and ensure dosage efficiency. The peptide antibody-drug bond facilitates rapid and efficient drug cleavage inside target tumor cell. The antibody cAC10 part of the drug binds to CD30 which often occurs on diseased cells but rarely on normal tissues. The antibody portion of the drug attaches to CD30 on the surface of malignant cells, delivering MMAE which is responsible for the anti-tumour activity. Once bound, brentuximab vedotin is internalised by endocytosis and thus selectively taken up by targeted cells. The vesicle containing the drug is fused with lysosomes and lysosomal cysteine proteases, particularly cathepsin B, start to break down valine-citrulline linker and MMAE is no longer bound to the antibody and is released directly into the tumor environment.
Sources: en.wikipedia.org
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Several antibiotics exert their action by targeting the translation process in bacteria. They exploit the differences between bacterial and eukaryotic translation mechanisms to selectively inhibit protein synthesis in bacteria without affecting the host.
The Philippines acquired 103 P-51D Mustangs after World War II, operated by the 6th "Cobras", 7th "Bulldogs" and 8th "Scorpions" tactical fighter squadrons of the 5th Fighter Wing. These became the backbone of the postwar Philippine Army Air Corps and Philippine Air Force, and were used extensively during the Huk campaign, fighting against communist insurgents, as well as the suppression of Moro rebels led by Hadji Kamlon in southern Philippines until 1955. The Mustangs were also the first aircraft of the Philippine air demonstration team, which was formed in 1953 and given the name the Blue Diamonds the following year. The Mustangs were replaced by 56 F-86 Sabres in the late 1950s, but some were still in service for COIN roles up to the early 1980s. Poland During World War II, five Polish Air Force in Great Britain squadrons used Mustangs. The first Polish unit equipped (7 June 1942) with Mustang Mk Is was "B" Flight of 309 "Ziemi Czerwieńskiej" Squadron (an Army Co-Operation Command unit), followed by "A" Flight in March 1943. Subsequently, 309 Squadron was redesignated a fighter/reconnaissance unit and became part of Fighter Command. On 13 March 1944, 316 "Warszawski" Squadron received their first Mustang Mk IIIs; rearming of the unit was completed by the end of April. By 26 March 1944, 306 "Toruński" Sqn and 315 "Dębliński" Sqn received Mustangs Mk IIIs (the whole operation took 12 days). On 20 October 1944, Mustang Mk Is in 309 Squadron were replaced by Mk IIIs.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
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.