This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-04. Anything still debated is marked as such rather than presented as settled.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
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.
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.
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 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.
by Kimura). In 1981, Joseph Felsenstein proposed a four-parameter model (F81) in which the substitution rate corresponds to the equilibrium frequency of the target nucleotide. Hasegawa, Kishino, and Yano unified the two last models to a five-parameter model (HKY). After these pioneering efforts, many additional sub-models of the GTR model were introduced into the literature (and common use) in the 1990s. Other models that move beyond the GTR model in specific ways were also developed and refined by several researchers. Almost all DNA substitution models are mechanistic models (as described above). The small number of parameters that one needs to estimate for these models makes it feasible to estimate those parameters from the data. It is also necessary because the patterns of DNA sequence evolution often differ among organisms and among genes within organisms. The later may reflect optimization by the action of selection for specific purposes (e.g. fast expression or messenger RNA stability) or it might reflect neutral variation in the patterns of substitution. Thus, depending on the organism and the type of gene, it is likely necessary to adjust the model to these circumstances.
=== Size-Exclusion Chromatography (Gel Filtration) === Size-exclusion chromatography separates proteins based on their size. The stationary phase is composed of porous beads that allow smaller molecules to enter the pores while larger molecules pass around them. As a result, larger proteins elute first, followed by smaller ones. This method is particularly useful for desalting or removing small contaminants from protein samples.
== Carrier proteins == Albumin, carries thyroid hormones and other hormones, particularly fat soluble ones, fatty acids to the liver, unconjugated bilirubin, many drugs and Ca2+ Ceruloplasmin, carries copper Transcortin, carries cortisol, aldosterone and progesterone Haptoglobin, carries free hemoglobin released from erythrocytes Hemopexin, carries free heme released from hemoglobin IGF binding protein, carries insulin-like growth factor 1 Major urinary proteins, carries pheromones in rodents Retinol binding protein, carries retinol Sex hormone-binding globulin, carries sex hormones, specifically testosterone and estradiol Thyroxine-binding globulin, carries the thyroid hormones thyroxine (T4) and 3,5,3’-triiodothyronine (T3) Transthyretin, carries the thyroid hormone thyroxine (T4) Transferrin, carries iron ions in the ferric form (Fe3+) Vitamin D-binding protein, carries vitamin D
Peerschke EI, Ghebrehiwet B. Human blood platelets possess specific binding sites for C1q. J. Immunol. 1987;138:1537–41. Peerschke EI, Ghebrehiwet B. Identification and partial characterization of human platelet C1q binding sites. J. Immunol. 1988;141: 3505–11. Peerschke EI, Reid KB, Ghebrehiwet B. Platelet activation by C1q results in the induction of alpha IIb/beta 3 integrins (GPIIb-IIIa) and the expression of P-selectin and procoagulant activity. J Exp Med. 1993;178:579–87. Peerschke EI, Reid KB, Ghebrehiwet B. Identification of a novel 33-kDa C1q-binding site on human blood platelets. J. Immunol. 1994;152:5896–901.
Sources: en.wikipedia.org
The administrative divisions of the German Democratic Republic (commonly referred to as East Germany) were constituted in two different forms during the country's history. The GDR first retained the traditional German division into federated states called Länder, but in 1952 they were replaced with districts called Bezirke. Immediately before German reunification in 1990, the Länder were restored, but they were not effectively reconstituted until after reunification had completed.
GSK-3 inhibition also mediates an increase in the transcription of the transcription factor Tbet (Tbx21) and an inhibition of the transcription of the inhibitory co-receptor programmed cell death-1 (PD-1) on T-cells. GSK-3 inhibitors increased in vivo CD8(+) OT-I CTL function and the clearance of viral infections by murine gamma-herpesvirus 68 and lymphocytic choriomeningitis clone 13 as well as anti-PD-1 in immunotherapy.
Often, when British allies attempted military actions within several dozen miles or so of the sea, the Royal Navy would arrive, land troops and supplies, and aid the coalition's land forces in a concerted operation. Royal Navy ships even provided artillery support against French units when fighting strayed near enough to the coastline. The ability and quality of the land forces governed these operations. For example, when operating with inexperienced guerrilla forces in Spain, the Royal Navy sometimes failed to achieve its objectives because of the lack of manpower that the Navy's guerrilla allies had promised to supply.
Rudolph Emile 'Rudy' Tanzi is the Joseph P. and Rose F. Kennedy Professor of Neurology at Harvard University, and director of the Genetics and Aging Research Unit and director of the Henry and Allison McCance Center for Brain Health at Massachusetts General Hospital (MGH). Dr. Rudy Tanzi has been investigating the genetics of neurological disease since the 1980s. He co-discovered all three familial early-onset Alzheimer's disease (FAD) genes and several other neurological disease genes including that responsible for Wilson’s disease. His team was the first to use human stem cells to create three-dimensional cell culture organoids of AD, dubbed “Alzheimer's-in-a-Dish”. The 3-D model made drug screening for AD faster and more cost-effective. He has published over 800 research papers and has received the Metropolitan Life Award and Potamkin Prize, the two highest awards for Alzheimer’s research. He is also a member of the National Academy of Medicine and was on the TIME100 Most Influential People in the World list in 2015.
In addition to publishing numerous reviews of opera performances and concerts, Adorno's Four Songs for medium voice and piano, Op. 3, was performed in Berlin in January 1929. Between 1928 and 1930, Adorno took on a greater role within the editorial committee of the Musikblätter des Anbruchs. In a proposal for transforming the journal, he sought to use Anbruch to champion radical modern music against what he called the "stabilized music" of Pfitzner, the later Richard Strauss, as well as the neoclassicism of Stravinsky and Hindemith. During this period he published the essays "Night Music," "On Twelve-Tone Technique," and "Reaction and Progress." Yet his reservations about twelve-tone orthodoxy became steadily more pronounced. According to Adorno, twelve-tone technique's use of atonality can no more be regarded as an authoritative canon than can tonality be relied on to provide instructions for the composer. At this time Adorno struck up a correspondence with the composer Ernst Krenek, discussing problems of atonality and the twelve-tone technique. In a 1934 letter, he sounded a related criticism of Schoenberg:
Sources: en.wikipedia.org
Ring A is then expanded via the polyketide synthase pathway to incorporate L-serine into ring B (figure 3). Ring A fragment is transferred from the peptidyl carrier protein (PCP) to the acyl carrier protein (ACP) by a keto-synthase (KS) domain, followed by transfer to malonyl-ACP via decarboxylative Claisen condensation catalysed by the enzyme pigJ. This fragment is then able to react with the masked carbanion formed from the pyridoxal phosphate (PLP) mediated decarboxylation of L-serine, which cyclizes in a dehydration reaction to yield the second pyrrole ring. This intermediate is then modified by oxidation of the primary alcohol to the aldehyde, catalysed by pigM, and methylation (which incorporates a methyl group from L-methionine onto the alcohol at the 6-position) catalysed by pigF and pigN. This yields the core A-B ring structure ready for further transformations, including to the tambjamines as well as the prodiginines.
Soon after settling into his new home on Riverside Drive, Adorno met with Lazarsfeld in Newark, New Jersey, to discuss the Project's plans for investigating the impact of broadcast music. Although he was expected to embed the Project's research within a wider theoretical context, it soon became apparent that the Project was primarily concerned with data collection to be used by administrators for establishing whether groups of listeners could be targeted by broadcasts specifically aimed at them. Expected to make use of devices with which listeners could press a button to indicate whether they liked or disliked a particular piece of music, Adorno bristled with distaste and astonishment: "I reflected that culture was simply the condition that precluded a mentality that tried to measure it." Thus, Adorno suggested using individual interviews to determine listener reactions and, only three months after meeting Lazarsfeld, completed a 160-page memorandum on the Project's topic, "Music in Radio." Adorno was primarily interested in how musical material was affected by its distribution through the medium of radio and thought it imperative to understand how music was affected by its becoming part of daily life.
== External links == Overview of Glutathione S-Transferases Glutathione+S-Transferase at the U.S. National Library of Medicine Medical Subject Headings (MeSH) EC 2.5.1.18 Glutathione Vs Vitamic C Preparation of GST Fusion Proteins How Does Glutathione Work GST Gene Fusion System Handbook Archived 2008-12-05 at the Wayback Machine
In the presence of acid, hemiacetals can undergo an elimination reaction, losing the oxygen atom that once belonged to the parent aldehyde’s carbonyl group. These oxonium ions are powerful electrophiles, and react rapidly with a second molecule of alcohol to form new, stable compounds, called acetals. The whole mechanism of acetal formation from hemiacetal is drawn below.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.