A practical reference on TKPRPGP: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-05-17 and is reviewed periodically as new material appears.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
| 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 |
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
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.
The arachnoid layer was first described by Dutch physician Gerardus Blasius in 1664. In 1695, Humphrey Ridley first described the subarachnoid cisterns. He also contributed to the understanding of the blood-brain barrier, and accurately described the fifth cranial nerve ganglion with its branches. In 1699, Frederick Ruysch confirmed that the arachnoid mater formed a complete layer that surrounded the brain. Its current name is based on his description of its spiderlike morphology. Arachnoid granulations were first described by Italian physician Antonio Pacchioni who published his Dissertatio Epistolaris de Glandulis Conglobatis Durae Meningis Humanae in 1705. In seven articles from 1899 to 1902, Italian anatomist Giuseppe Sterzi described comparative studies on the meninges from the lancelet to the human. He showed that the spinal meninges were very simple in adult lower vertebrates and in the early development of more advanced vertebrates.
== Properties == Industrially produced vinylene carbonate is usually a yellow to brown liquid. By suitable process control and purification steps, a solid product with a melting point of 20-22 °C and a chlorine content below 10ppm can be obtained. Liquid vinylene carbonate turns rapidly yellow even in the absence of light and must be stabilized by the addition of radical scavengers. In solid form, the highly pure substance is long-term stable when stored below 10 °C. Vinylene carbonate dissolves in a variety of solvents such as ethanol, tetrahydrofuran, ethylene carbonate, propylene carbonate, and other dipolar aprotic electrolyte solvents used for lithium ion rechargeable batteries such as dimethyl carbonate, diethyl carbonate and the like.
Gleason (1938), music critic for the San Francisco Chronicle and co-founder of Rolling Stone Eugene Williams (1938), jazz critic, founder of Jazz Information Allan Temko (1947), architecture critic of the San Francisco Chronicle and winner of the Pulitzer Prize for Criticism Andrew Sarris (1951), film critic Martin Gottfried (1955), critic, author, and biographer Donald Kuspit (1955), art critic Morris Dickstein (1961), cultural critic and professor at The Graduate Center, CUNY David Denby (1965), film critic for The New Yorker Michael Feingold (1966), lead theater critic for The Village Voice Martin Filler (1970), architecture critic Gerrit Henry (1972), art critic, author, poet Jed Perl (1972), art critic; son of Nobel laureate Martin Lewis Perl GSAS '55 Lucy Sante (1976), literary critic Tim Page (1979), music critic of The Washington Post and winner of the Pulitzer Prize for Criticism Jonathan Beller (1985), cultural critic, professor at Pratt Institute Michael Riedel (1989), theater critic for New York Post Ben Ratliff (1990), journalist and music critic Neil Strauss (1991), music critic and best-selling author Justin Shubow (1999), architectural critic, former chairman and member of the United States Commission of Fine Arts Helena Andrews (2002), pop culture critic
The College of American Pathologists (CAP) is a member-based physician organization founded in 1946, comprising approximately 18,000 board-certified pathologists. It serves patients, pathologists, and the public by fostering and advocating best practices in pathology and laboratory medicine. It is the world's largest association composed exclusively of pathologists certified by the American Board of Pathology, and is widely considered the leader in laboratory quality assurance. The CAP is an advocate for high-quality and cost-effective medical care. The CAP currently inspects and accredits medical laboratories under authority from the Centers for Medicare & Medicaid Services. Their standards have been called "the toughest and most exacting in the medical business." The CAP provides resources and guidance to laboratories seeking accreditation in programs for biorepositories, genomics, ISO 15189, and more. In November 2008, Piedmont Medical Laboratory of Winchester, Virginia became the first laboratory in the United States to be officially accredited under ISO 15189. The CAP provides accreditation and proficiency testing to medical laboratories through its laboratory quality solutions programs. Early versions of proficiency testing—known as surveys—which laboratories use to help test and ensure accuracy, were first initiated in 1949. Laboratories first began receiving CAP accreditation in 1964, and the organization was later given authority to accredit medical laboratories as a result of the Clinical Laboratory Improvement Amendments of 1988.
Sources: en.wikipedia.org
Sirolimus, also known as rapamycin and sold under the brand name Rapamune among others, is a macrolide compound that is used to coat coronary stents, prevent organ transplant rejection, treat a rare lung disease called lymphangioleiomyomatosis, and treat perivascular epithelioid cell tumour (PEComa). It has immunosuppressant functions in humans and is especially useful in preventing the rejection of kidney transplants. It is a mammalian target of rapamycin (mTOR) kinase inhibitor that reduces the sensitivity of T cells and B cells to interleukin-2 (IL-2), inhibiting their activity. This compound also has a use in cardiovascular drug-eluting stent technologies to inhibit restenosis.
== Medical characterization of gender variance == Gender variance is defined in medical literature as "gender identity, expression, or behavior that falls outside of culturally defined norms associated with a specific gender". For centuries, gender variance was seen by medicine as a pathology. The World Health Organization identified gender dysphoria as a mental disorder in the International Classification of Diseases (ICD) until 2018. Gender dysphoria was also listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) of the American Psychiatric Association, where it was previously called "transsexualism" and "gender identity disorder". In 2018, the ICD-11 included the term "gender incongruence" as "marked and persistent incongruence between an individual's experienced gender and the assigned sex", where gender variant behaviour and preferences do not necessarily imply a medical diagnosis. However, the difference between "gender dysphoria" and "gender incongruence" is not always clear in the medical literature. Some studies posit that treating gender variance as a medical condition has negative effects on the health of transgender people and claim that assumptions of coexisting psychiatric symptoms should be avoided. Other studies argue that gender incongruence diagnosis may be important and even positive for transgender people at the individual and social level.
Another diagnostic technique is the real-time quaking-induced conversion assay, which can detect the disease in early stages. There is currently no specific treatment for CJD. Opioids may be used to help with pain, while clonazepam or sodium valproate may help with involuntary movements. CJD affects about one person per million people per year. Onset of sporadic CJD is typically around 60 years of age.
Early examples of organic reactions and applications were often found because of a combination of luck and preparation for unexpected observations. The latter half of the 19th century however witnessed systematic studies of organic compounds. The development of synthetic indigo is illustrative. The production of indigo from plant sources dropped from 19,000 tons in 1897 to 1,000 tons by 1914 thanks to the synthetic methods developed by Adolf von Baeyer. In 2002, 17,000 tons of synthetic indigo were produced from petrochemicals. In the early part of the 20th century, polymers and enzymes were shown to be large organic molecules, and petroleum was shown to be of biological origin. The multiple-step synthesis of complex organic compounds is called total synthesis. Total synthesis of complex natural compounds increased in complexity to glucose and terpineol. For example, cholesterol-related compounds have opened ways to synthesize complex human hormones and their modified derivatives. Since the start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B12.
=== Antipsychotics === Olanzapine and risperidone are atypical antipsychotics which are also effective in GAD and PTSD treatment. However, there is a higher chance of experiencing adverse effects than the other anti-anxiety medications.
Sources: en.wikipedia.org
An adenylating enzyme (Ad) catalyzes the condensation of decanoic acid and the N-terminal tryptophan, which incorporates decanoic acid into the growing peptide (Figure 3). The genes responsible for this coupling event are dptE and dptF, which are located upstream of dptA, the first gene of the Daptomycin NRPS biosynthetic gene cluster. Once the coupling of decanoic acid to the N-terminal tryptophan residue occurs, the condensation of amino acids begins, catalyzed by the NRPS. The first five modules of the NRPS are encoded by the dptA gene and catalyze the condensation of L-tryptophan, D-asparagine, L-aspartate, L-threonine, and glycine, respectively (Figure 4). Modules 6–11, which catalyze the condensation of L-ornithine, L-aspartate, D-alanine, L-aspartate, glycine, and D-serine are encoded for the dptBC gene (Figure 5). dptD catalyzes the incorporation of two nonproteinogenic amino acids, L-3-methylglutamic acid (mGlu) and Kyn, which is only known thus far to daptomycin, into the growing peptide (Figure 6). Elongation by these NRPS modules ultimately leads to macrocyclization and release in which an α-amino group, namely threonine, acts as an internal nucleophile during cyclization to yield the 10-amino-acid ring (Figure 6). The termination module in the NRPS assembly line has a C-A-T-TE organization. The thioesterase domain catalyzes chain termination and release of the mature lipopeptide. The molecular engineering of daptomycin, the only marketed acidic lipopeptide antibiotic to date (Figure 8), has seen many advances since its inception into clinical medicine in 2003.
Biological value (BV) is a measure of the proportion of absorbed protein from a food which becomes incorporated into the proteins of the organism's body. It captures how readily the digested protein can be used in protein synthesis in the cells of the organism. Proteins are the major source of nitrogen in food. BV assumes protein is the only source of nitrogen and measures the amount of nitrogen ingested in relation to the amount which is subsequently excreted. The remainder must have been incorporated into the proteins of the organisms body. A ratio of nitrogen incorporated into the body over nitrogen absorbed gives a measure of protein "usability" – the BV. Unlike some measures of protein usability, biological value does not take into account how readily the protein can be digested and absorbed (largely by the small intestine). This is reflected in the experimental methods used to determine BV. BV uses two similar scales:
The government dissolved the National Assembly in its first days and the cabinet ruled by ordinance-laws signed by the tsar, invoking Article 47 of the Tarnovo Constitution. On 14 June political parties and trade unions were banned and their property was nationalised. Counties and municipalities were clustered, their self-government abolished and replaced by government-appointed officials. Stricter qualification criteria for teachers were introduced, dozens of schools were closed and over 2,000 teachers were left unemployed. A campaign was organized to replace the traditional names of many villages in the country with Bulgarian ones. Strict censorship was introduced and many printed publications were banned. In order to increase state revenues and subsidize agriculture, the government established state monopolies in the grain, alcohol, and tobacco trades, severely disrupting activity in these sectors. Up to 40% of debts that were difficult to service after the Great Depression were cancelled, the rest were rescheduled, and enforcement measures were limited. Several distressed private banks were consolidated and reactivated with state capital to form the Bulgarian Credit Bank. The two large state-owned banks were also merged into the Bulgarian Agricultural and Cooperative Bank. A Public Assistance Service was established under the Ministry of the Interior, financed by a special tax, and free treatment of the poor in public hospitals was introduced.
In 2021 a 5Å CryoEM analysis revealed the relationship between the catalytic domains and the intact TPR regions confirming the dimer arrangement first seen in the TPR alone X ray structure. This structure supports an ordered sequential bi-bi mechanism that matches the fact that “at saturating peptide concentrations, a competitive inhibition pattern was obtained for UDP with respect to UDP-GlcNAc.”
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.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.