A practical reference on tuftsin: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-04. Anything still debated is marked as such rather than presented as settled.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
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.
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.
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.
Be the single controlling body and administrator of the Game; Foster, develop, extend and provide adequate funding for the Game from the junior to elite levels and generally to act in the best interests of the Game; Liaise with and delegate appropriate functions to governing bodies of the Game in the States and Territories of Australia, including the NSWRL and QRL; Organise and conduct all State of Origin and Australian Representative Games; Organise, conduct and foster the NRL Competition; Liaise with the Rugby League International Federation Limited and organisations controlling the game in other countries in the fostering and control of the game of Rugby League throughout the world; Promote and encourage either directly or indirectly the physical, cultural and intellectual welfare of young people in the community and, in particular, the Rugby League community; Promote and encourage either directly or indirectly sport and recreation, particularly Rugby League football, in the interests of the social welfare of young persons.
=== Value Menu === In 2012, A&W introduced its first value burger, the Buddy Burger, and its double patty variant, the Double Buddy burger. Both can be ordered with or without cheese. The release of the Buddy burger made A&W more competitive against McDonald's, who already had value burgers like the McDouble. In 2015, A&W piloted the new Chicken Buddy burger at some select locations. It was successful and was added to the value menu permanently in 2016.
The two substrates of this enzyme are 1-octanol and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 1-octanal, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is octanol:NAD+ oxidoreductase. This enzyme is also called 1-octanol dehydrogenase.
Sources: en.wikipedia.org
== Further reading == Milosevic, V., Edelmann, R.J., Fosse, J.H., Östman, A., Akslen, L.A. (2022). Molecular Phenotypes of Endothelial Cells in Malignant Tumors. In: Akslen, L.A., Watnick, R.S. (eds) Biomarkers of the Tumor Microenvironment. Springer, Cham. https://doi.org/10.1007/978-3-030-98950-7_3
=== Nile red === Nile red (also known as Nile blue oxazone) is formed by boiling Nile blue with sulfuric acid. This produces a mix of Nile red and Nile blue. Nile red is a lipophilic stain; it will accumulate in lipid globules inside cells, staining them red. Nile red can be used with living cells. It fluoresces strongly when partitioned into lipids, but practically not at all in aqueous solution.
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Sources: en.wikipedia.org
=== Differential diagnosis and comorbidity === Lifetime comorbid conditions are prevalent among individuals diagnosed with BPD. Individuals with BPD exhibit higher rates of comorbidity compared to those diagnosed with other personality disorders. These comorbidities include mood disorders (such as major depressive disorder and bipolar disorder), anxiety disorders (including panic disorder, social anxiety disorder, and post-traumatic stress disorder (PTSD)), other personality disorders (notably schizotypal, antisocial, and dependent personality disorder), substance use disorder, eating disorders (anorexia nervosa and bulimia nervosa), attention deficit hyperactivity disorder (ADHD), somatic symptom disorder, and the dissociative disorders. It is advised that a personality disorder diagnosis should be made cautiously during untreated mood episodes or disorders unless a comprehensive lifetime history supports the existence of a personality disorder.
Helium liquifies when cooled below 4.2 K (−268.95 °C; −452.11 °F) at atmospheric pressure. Unlike any other element, however, helium remains liquid down to a temperature of absolute zero. This is a direct effect of quantum mechanics: specifically, the zero point energy of the system is too high to allow freezing. Pressures above about 2.5 MPa (25 atm) are required to freeze it. There are two liquid phases: Helium I is a conventional liquid, and Helium II, which occurs at a lower temperature, is a superfluid.
The thymus increases in size from birth in response to postnatal antigen stimulation. It is most active during the neonatal and pre-adolescent periods. The thymus is located between the inferior neck and the superior thorax. During adolescence, the thymus begins to atrophy and regress, with adipose tissue mostly replacing the thymic stroma. However, residual T cell lymphopoiesis continues throughout adulthood, providing some immune response. The thymus is where the T lymphocytes mature and become immunocompetent. The absence of the thymus (whether congenital or due to loss of the thymus gland) results in severe immunodeficiency and subsequent high susceptibility to infection. In most species, the thymus consists of lobules divided by septa. These are composed of epithelium. T cells mature from thymocytes, proliferate, and undergo a selection process in the thymic cortex before entering the medulla to interact with epithelial cells. Research on bony fish showed a buildup of T cells in the thymus and spleen of lymphoid tissues in salmon and showed that there are not many T cells in non-lymphoid tissues. The thymus provides an inductive environment for developing T cells from hematopoietic progenitor cells. In addition, thymic stromal cells facilitate the selection of a functional and self-tolerant T cell repertoire. Therefore, one of the most important roles of the thymus is the induction of central tolerance. However, the thymus is not where the infection is fought, as the T cells have yet to become immunocompetent.
The multiaxial diagnostic system of previous editions has been eliminated with the introduction of the DSM-5, with all disorders, including personality disorders, being integrated into Section II of the manual. For a diagnosis of BPD, an individual must meet five out of nine specified diagnostic criteria. The DSM-5 characterizes BPD as a pervasive pattern of instability in interpersonal relationships, self-image, affect, and a significant propensity towards impulsive behavior. Marsha Linehan highlights the diagnostic challenges faced by mental health professionals in using the DSM criteria due to the broad range of behaviors they encompass. To mitigate these challenges, Linehan categorizes BPD symptoms into five principal areas of dysregulation: emotions, behavior, interpersonal relationships, sense of self, and cognition. Moreover, the Alternative DSM-5 Model for Personality Disorders (AMPD), located in Section III of the DSM-5, defines six specific personality disorders—one of them being BPD—in terms of a description of the disorder; the characteristic manner in which the disorder impacts personality functioning, i.e. identity, self-direction, empathy and intimacy (criterion A); as well as a listing and description of the pathological personality traits associated with the disorder (criterion B).
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.