Everything below concerns tuftsin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
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.
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
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.
== Causes == The American Cancer Society noted that several factors contributed to escalating nationwide drug shortages, which included decreased or restricted drug manufacturing capacity, increased drug demands coupled with corresponding shortages in supplies, and lower profit margins for several generic drugs decreasing corporate desires towards creating surpluses. The organization also noted that the Food and Drug Administration's means to prevent drug shortages were fundamentally centered around contact with the drug manufacturers involved, giving early warnings that requested them to increase production instead of directly pushing for specific drug quotas. The ASHP reported that one of the main causes of continuous severe shortages was due to "extreme price competition" between generic drug manufacturers. Challenges to quick-enough production of high-quality medications coupled with possible supply chain disruptions pushed many of these companies to shift their manufacturing to producing drugs with higher profit margins, with some completely stopping production of less lucrative drugs. The organization also pointed out the role that difficult and multi-year federal regulatory approval processes for new manufacturers played in lowering the number of new drug manufacturers and resulting supply decreases. Generic drug user fees noted in section 506C(g) of the Federal Food Drug and Cosmetics Act further made it difficult for companies to keep their businesses profitable. U.S.
== SPE and chromatography == SPE is in fact a method of chromatography, in the sense of having a mobile phase, carrying mixtures through a stationary phase, packed inside a column. The chromatographic process is harnessed to create a solid-liquid extractive technique—allowing separation of a mixture of components by taking advantage of large differences between the solid and liquid phase Keq, or equilibrium constant, for each component in the mixture. The chemical considerations for the selection of stationary and mobile phases are similar to those for liquid column chromatography and many of the adsorbents/materials used are the same. The theory, procedures, and aims are different, however, and as an extractive technique it has a unique niche in modern chemical science.
== Codon assignment == Another element of the system is a codon to allocate to the new amino acid. A major problem for the genetic code expansion is that there are no free codons. The genetic code has a non-random layout that shows tell-tale signs of various phases of primordial evolution, however, it has since frozen into place and is near-universally conserved. Nevertheless, some codons are rarer than others. In fact, in E. coli (and all organisms) the codon usage is not equal, but presents several rare codons (see table), the rarest being the amber stop codon (UAG).
==== Military service (1954–55) ==== With the Korean War occurring, Mizell had been drafted to serve in the United States Army as early as 1952, but he managed to get his service deferred twice because he was the support for his mother and grandmother. Finally, shortly after the 1953 season ended, he reported to Fort McPherson, Georgia, where he would be stationed for the next two years. Mizell, who walked with a "two-furrow" stride, had to make a special effort not to step on the heels of the soldier in front of him when he was marching in ranks. He saw no combat, instead winning 36 games (with only two losses) for the fort's baseball team. Mizell threw four no-hitters and 16 shutouts, helping the team reach the Army baseball championship tournament at Fort Belvoir, Virginia, in 1955. A sergeant by the time he was discharged, Mizell had struck out 324 batters in two years of service.
Sources: en.wikipedia.org
=== Biochemistry === Guanidine exists protonated, as guanidinium, in solution at physiological pH. Guanidinium chloride (also known as guanidine hydrochloride) has chaotropic properties and is used to denature proteins. Guanidinium chloride is known to denature proteins with a linear relationship between concentration and free energy of unfolding. In aqueous solutions containing 6 M guanidinium chloride, almost all proteins lose their entire secondary structure and become randomly coiled peptide chains. Guanidinium thiocyanate is also used for its denaturing effect on various biological samples. Recent studies suggest that guanidinium is produced by bacteria as a toxic byproduct. To alleviate the toxicity of guanidinium, bacteria have developed a class of transporters known as guanidinium exporters or Gdx proteins to expel the extra amounts of this ion to the outside of the cell. Gdx proteins are highly selective for guanidinium and mono-substituted guanidinyl compounds and share an overlapping set of non-canonical substrates with drug exporter EmrE.
The colony's participation in the Empire Air Training Scheme is described in J F MacDonald's War History of Southern Rhodesia as "undoubtedly Southern Rhodesia's greatest single contribution to the Allied victory", an assertion corroborated by Robert Blake in his 1977 History of Rhodesia. The Rhodesian Air Training Group (RATG) under Air Vice-Marshal Sir C W Meredith eventually operated 11 aerodromes, requiring a huge national effort to build, maintain and staff—at the scheme's peak more than a fifth of the white population was involved. This judicious management of skills and resources allowed the territory to make a much larger contribution to the Allied war effort than if it had simply sent all its manpower into the field. Southern Rhodesia was regarded as an ideal location for air training for a number of reasons. It was far from the hostilities, firmly pro-British and had excellent weather throughout the year. The British Air Ministry resolved to outsource training to the colony amid some urgency in late 1939 after EATS took a long time to get going in Canada. The RATG was the last EATS group to be formed, but the first to start training airmen; it also turned out fully qualified pilots before any of the others, doing so for the first time in November 1940. The programme originally called only for an initial training wing and six schools, but this was expanded to eight flying schools and a school for bomb aimers, navigators and air gunners. There were two air firing and bombing ranges.
Oberstleutnant Wilhelm-Hunold von Stockhausen, July 1939 – February 1940 Oberstleutnant Gerhard Graf von Schwerin, February 1940 – March 1940 Oberst Wilhelm-Hunold von Stockhausen, March 1940 – August 1941 Oberst Walter Hörnlein, August 1941 – April 1942 Infantry/Panzergrenadier Division Großdeutschland
Acoustic resonance spectroscopy is based on sound waves primarily in the audible and ultrasonic regions. Auger electron spectroscopy is a method used to study surfaces of materials on a micro-scale. It is often used in connection with electron microscopy. Cavity ring-down spectroscopy enables measurement of absolute optical extinction by samples that scatter and absorb light. Circular dichroism spectroscopy measures the differential absorption of left- and right-handed circularly polarized light. Coherent anti-Stokes Raman spectroscopy is a recent technique that has high sensitivity and powerful applications for in vivo spectroscopy and imaging. Cold vapour atomic fluorescence spectroscopy is a subclass of the atomic emission spectroscopy technique that measures trace amounts of volatile heavy metals in the air, such as mercury. Correlation spectroscopy encompasses several types of two-dimensional NMR spectroscopy. Deep-level transient spectroscopy measures concentration and analyzes parameters of electrically active defects in semiconducting materials. Dielectric spectroscopy measures the dielectric properties of a medium as a function of frequency. Dual-polarization interferometry measures the real and imaginary components of the complex refractive index. Electron energy loss spectroscopy in transmission electron microscopy. Electron phenomenological spectroscopy measures the physicochemical properties and characteristics of the electronic structure of multicomponent and complex molecular systems.
The Codon Adaptation Index (CAI) is the most widespread technique for analyzing codon usage bias. As opposed to other measures of codon usage bias, such as the 'effective number of codons' (ENc), which measure deviation from a uniform bias (null hypothesis), CAI measures the deviation of a given protein coding gene sequence with respect to a reference set of genes. CAI is used as a quantitative method of predicting the level of expression of a gene based on its codon sequence.
Sources: en.wikipedia.org
APHL monitors trends in public health laboratory diagnostics, personnel and infrastructure. It uses this data to benchmark against national norms and to define issues of importance to lab practice and policy. APHL also disseminates research findings via issue briefs and communications with federal decision makers, health partners and the laboratory community. Members have access to survey data online, enabling them to leverage this information quickly to identify promising strategies and practices. In an effort to improve laboratory practice, APHL provides free resources, such as tools kits that explain how to: Write a laboratory quality manual Conduct an internal audit Recruit students in STEM fields Deal with laboratory floods In addition to on-demand research and reports, APHL provides continuing education courses to help laboratory scientists keep up with emerging trends, and innovative testing techniques. Training sessions are conducted through conferences, seminars, workshops and online courses.
Based on its amino acid profile C-5 sterol desaturase appears to have four to five membrane-spanning regions, suggesting that it is a transmembrane protein. C5SD activity has been demonstrated in microsomes from rat tissue, implying that rat enzyme localizes to the endoplasmic reticulum Fluorescence microscopy experiments have shown that in the ciliate Tetrahymena thermophila C5SD localizes to the endoplasmic reticulum and that in S. cerevisiae C5SD localizes to both the endoplasmic reticulum and vesicles. In Arabidopsis thaliana C5SD is located in both the endoplasmic reticulum and lipid particles.
It has been shown that endoglin expression and TGF-beta secretion are attenuated in bone marrow stromal cells when they are cocultured with prostate cancer cells. Also, the downstream TGF-beta/bone morphogenic protein (BMP) signaling pathway, which includes Smad1 and Smad2/3, were attenuated along with Smad-dependent gene transcription. Another result in this study was that both Smad1/5/8-dependent inhibitor of DNA binding 1 expression and Smad2/3-dependent plasminogen activator inhibitor I had a reduction in expression and cell proliferation. Ultimately, the cocultured prostate cancer cells altered the TGF-beta signaling in the bone stromal cells, which suggests this modulation is a mechanism of prostate cancer metastases facilitating their growth and survival in the reactive bone stroma. This study emphasizes the importance of endoglin in TGF-beta signaling pathways in other cell types other than endothelial cells. TRC105 is an experimental antibody targeted at endoglin as an anti-angiogenesis treatment for soft-tissue sarcoma. Cluster of differentiation
44. Adv Gerontol. 2004;13:90-3. [Effect of epitalon on the immunity and hemostasis in hypophysectomized chicken and old hens]. [Article in Russian] Kuznik BI, Pateiuk AV, Khavinson VKh, Malinin VV. Neonatal hypophysectomy in chicken, as well as that in old hen has been established to entail in 1,5 months after surgery cellular and humoral immunity disturbances, pronounced hypercoagulation and fibrinolysis depression. Administration of Epitalon (Ala-Glu-Asp-Gly) to a large extent eliminates revealed shifts. This effect appeared to be stronger in neonatally hypophysectomized chicken than in old hens.
==== Topical preparations ==== Cosmetics may contain a non-gelling variant of gelatin under the name hydrolyzed collagen (hydrolysate). Hydrolyzed collagen may be found in topical (applied to the skin) creams, acting as a product texture conditioner, and moisturizer.
Sources: en.wikipedia.org
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.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
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.