Everything below concerns Pro-Gly-Pro. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
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.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
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.
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 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 treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
== Ingredients == The sauce is made primarily of dried chili peppers, chili powder, broad bean paste, Sichuan peppercorn, clove, garlic, star anise, black cardamom, fennel, ginger, cinnamon, salt and sugar. These ingredients are simmered with beef tallow and vegetable oil for many hours, and packed into a jar. Other herbs and spices, such as sand ginger, Angelica dahurica and poppy seeds, can be added to create a unique flavor profile. Traditionally, a restaurant hired a chef specializing in making this sauce; the recipes were kept secret to the chef himself. Today, prepared mala sauce can easily be found in supermarkets, and chain restaurants often produce their own sauce on a large scale, while many others still blend their own. Like curry, there is a constant debate about the 'best' recipe and numerous variations are available on the market.
=== Phase 3 === Altropane (123-I Altropane; [123I]-E-IACFT; NAV-5001; O-587) – dopamine reuptake inhibitor (DRI) and single-photon emission-computed tomography (SPECT) enhancer [3] Apomorphine (Aporon) – non-selective dopamine receptor agonist and other actions [4] Apomorphine sublingual film (APL-130277; Kynmobi) – non-selective dopamine receptor agonist and other actions [5] Bemdaneprocel (BRT-DA01; DA-01; MSK-DA01; pluripotent stem cell derived dopaminergic neurons) – dopaminergic cell replacement [6] Buntanetap ((+)-(3aR)-phenserine; (+)-phenserine; ANVS-401; ANVS-405; ANVS402; posiphen) – various actions [7] 18F-LBT-999 ([18F]-LBT-999; LBT-999) – dopamine reuptake inhibitor (DRI) and positron-emission tomography (PET) enhancer – diagnosis [8] Nabilone controlled release (Nabilone FDT) – cannabinoid CB1 and CB2 receptor agonist [9] Pramipexole/rasagiline (P2B-001; rasagiline/pramipexole) – combination of pramipexole (dopamine D2-like receptor agonist) and rasagiline (MAO-B inhibitor) [10] Remlifanserin (ACP-204) – serotonin 5-HT2A receptor antagonist – Parkinson's disease psychosis [11] Solengepras (CVN-424) – G protein-coupled receptor 6 (GPR6) inhibitor [12] Tavapadon (CVL-751; PF-6649751; PF-06649751) – dopamine D1 and D5 receptor agonist [13]
=== Photodegradation === Additionally, DBNPA is prone to light-induced degradation, especially when exposed to ultraviolet (UV) radiation. Photocatalytic breakdown leads to debromination and the formation of less reactive intermediates, further accelerating its degradation in aqueous systems.
==== Waterboarding ==== Hitchens was asked by Vanity Fair to experience waterboarding for himself at a U.S. Army training facility. In May 2008, Hitchens voluntarily underwent the procedure. Hitchens stopped the procedure after 11 seconds and subsequently endorsed the view that it was "torture." He concluded, "If waterboarding does not constitute torture, then there is no such thing as torture."
The minimum bactericidal concentration (MBC) is the lowest concentration of an antibacterial agent required to kill a particular bacterium. It can be determined from broth dilution minimum inhibitory concentration (MIC) tests by subculturing to agar plates that do not contain the test agent. The MBC is identified by determining the lowest concentration of antibacterial agent that reduces the viability of the initial bacterial inoculum by ≥99.9%. The MBC is complementary to the MIC; whereas the MIC test demonstrates the lowest level of antimicrobial agent that inhibits growth, the MBC demonstrates the lowest level of antimicrobial agent that results in microbial death. This means that even if a particular MIC shows inhibition, plating the bacteria onto agar might still result in organism proliferation because the antimicrobial did not cause death. Antibacterial agents are usually regarded as bactericidal if the MBC is no more than four times the MIC. Because the MBC test uses colony-forming units as a proxy measure of bacterial viability, it can be confounded by antibacterial agents which cause aggregation of bacterial cells. Examples of antibacterial agents which do this include flavonoids and peptides.
Sources: en.wikipedia.org
== Other uses == The synthesis of 6-acetyl-1,2,3,4-tetrahydropyridine, an important bread aroma compound, starting from 2-piperidone was accomplished using t-boc anhydride. (See Maillard reaction). The first step in this reaction sequence is the formation of the carbamate from the reaction of the amide nitrogen with boc anhydride in acetonitrile using DMAP as a catalyst.
==== Structure ==== There are three structural zones in articular cartilage including a superficial tangential zone, a middle transitional zone and a deep zone. In the tangential zone, collagen fibers are aligned parallel to the surface and become gradually randomly aligned while moving into the deep zone. Collagen fibers in the superficial zone are aligned parallel to the surface in order to restrict shear stresses. Similarly, collagen fibers are aligned perpendicular to the surface in the deep zone in order to restrict compressive forces. Between bone and the deep zone lies calcified cartilage. Cell arrangement also varies between the zones, in deeper zones chondrocytes are stacked into columns while in the superficial zones they are arranged randomly. In the superficial regions the cells are also more elongated, while in deeper zones they are more spherical in nature.
Hyaline cartilage is the glass-like (hyaline) and translucent cartilage found on many joint surfaces. It is also most commonly found in the ribs, nose, larynx, and trachea. Hyaline cartilage is pearl-gray in color, with a firm consistency and has a considerable amount of collagen. It contains no nerves or blood vessels, and its structure is relatively simple.
== Bromine-77 == Bromine-77 is the most stable radioisotope of bromine, with a half-life of 57.04 hours. Although β+ decay is possible for this isotope, about 99.3% of decays are by electron capture. Despite its complex emission spectrum, featuring strong gamma-ray emissions at 239, 297, 521, and 579 keV, 77Br was used in SPECT imaging in the 1970s. However, except for longer-term tracing, this is no longer considered practical due to the difficult collimator requirements and the proximity of the 521 keV line to the 511 keV annihilation radiation related to the β+ decay. The Auger electrons emitted during decay are nevertheless well-suited for radiotherapy, and 77Br can possibly be paired with the imaging-suited 76Br (produced as an impurity in common synthesis routes) for this application.
== History == The use of generative artificial intelligence to create sexually explicit images emerged in 2022 on platforms such as Reddit and 4chan. AI-generated pornography became widespread in the early 2020s following Stability AI's release of Stable Diffusion (SD). This open-source model enables the creation of images from text prompts, utilizing the LAION-5B dataset. Following the model's public release, the volume of both explicit and non-explicit AI-generated media content increased. Due to the open-source nature of Stable Diffusion, there were no restrictions on image generation, which led to controversies regarding open-access AI and its use in generating explicit content. Over time, open-source AI models improved, enabling the creation of highly realistic images and intensifying calls for regulation in this area.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.