The short version of Neurotrophic factor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-25 and is reviewed periodically as new material appears.
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.
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.
| 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 |
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
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.
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.
An exchange of ions (charged atoms) across the nerve cell membrane sends a depolarizing current towards the end of the nerve cell (cell terminus). When the depolarizing current arrives at the nerve cell terminus, the neurotransmitter acetylcholine (ACh), which is held in vesicles, is released into the space between the two nerves (synapse). It moves across the synapse to the postsynaptic receptors. ACh binds to the receptors and transfers the signal to the target cell, and after a short time, it's destroyed by acetylcholinesterase.
== Career at Genentech == Because of the Kleiner and Perkins investment, Swanson and Boyer dissolved their partnership and created the legal entity Genentech. Kleiner and Perkins provided $100,000 on the May closing, and acquired 20,000 shares of preferred stock from Genentech. Swanson was made the president and treasurer of Genentech, and received a $2,500 per month salary, along with 25,000 shares. This marked the end of Swanson's unemployment, and the beginning of his career at Genentech. With funding secured, and the organizational structure formed, the first logical step forward was to begin experimenting with the procedure for the synthesis of insulin. Since Genentech lacked any laboratories of its own, the Boyer lab, as well as two other labs in the San Francisco area, were to be subcontracted to carry out the experiments. However, the scientists quickly realized that a step wise approach would be more practical; rather than immediately engineer a bacterium that synthesized insulin, they would engineer a bacterium that could synthesize somatostatin, a smaller hormone. Swanson resisted at first, since he believed that “If you are going to go for something, go for the real thing.” the "real thing" being insulin, in this case. He eventually agreed, albeit grudgingly. With a new research goal set up, Swanson proceeded to establish official research agreements with the institutions. He set up research agreements with the University of California and the City of Hope. Then, in early 1977, Swanson began a second round of funding, to jumpstart the somatostatin research.
Ariel Fernandez (born Ariel Fernández Stigliano, April 8, 1957) is an Argentinian–American physical chemist and pharmaceutical researcher. In 2025, a judge determined that Fernandez had engaged in scientific misconduct, and in 2026 he was barred from receiving federal research funding in the US for 15 years. Fernandez denies the misconduct findings.
== Symptoms and signs == Symptoms of cardiac amyloidosis are a combination of heart failure and amyloid deposition in various other organs. Amyloid deposition in the heart causes restrictive diastolic heart failure that progresses to systolic heart failure. Cardiac manifestations include:
== Construction == A variety of constructions are available. Most have an internal thermistor or thermocouple or can be connected to external sources. Sampling and measurement are periodically taken and digitally stored. Some have a built in display of data or out-of-tolerance warnings. Data retrieval can be by cable, RFID, wireless systems, etc. They generally are small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors. Some data loggers interface with personal computers or smart phones for set-up, control, and analysis. Some include other sensors such as relative humidity, wind, light, tilt, shock, vibrations etc. Others may record input from GPS devices. Depending on the use, governing quality management systems sometimes require calibration to national standards and compliance with formal verification and validation protocols Choices of temperature data loggers can be based on many factors, such as:
Sources: en.wikipedia.org
June 11, 2009: Bulgaria Bulgarian authorities declare the country is officially in recession after dropping 1.6% in the last quarter of 2008, followed by a 5% drop in the first quarter of 2009. Unemployment is rising rapidly and by September 500,000 people are expected to lose their jobs. Exports are down 50%. For the first three months of 2009 GDP has shrunk by 2%. Households and small businesses are heavily in debt.
Several disease courses (or types) of MS have been described. They are used to help predict the progression of MS for individuals, for clinical trials and for decisions on what medications to use. The International Advisory Committee on Clinical Trials of MS classifies MS courses into four disease courses in what is known as the Lublin-Reingold classification:
=== Approaches === In keeping with the performance and mass range of available mass spectrometers, two approaches are used for characterizing proteins. In the first, intact proteins are ionized by either of the two techniques described above, and then introduced to a mass analyzer. This approach is referred to as "top-down" strategy of protein analysis as it involves starting with the whole mass and then pulling it apart. The top-down approach however is mostly limited to low-throughput single-protein studies due to issues involved in handling whole proteins, their heterogeneity and the complexity of their analyses. In the second approach, referred to as the "bottom-up" MS, proteins are enzymatically digested into smaller peptides using a protease such as trypsin. Subsequently, these peptides are introduced into the mass spectrometer and identified by peptide mass fingerprinting or tandem mass spectrometry. Hence, this approach uses identification at the peptide level to infer the existence of proteins pieced back together with de novo repeat detection. The smaller and more uniform fragments are easier to analyze than intact proteins and can be also determined with high accuracy, this "bottom-up" approach is therefore the preferred method of studies in proteomics. A further approach that is beginning to be useful is the intermediate "middle-down" approach in which proteolytic peptides larger than the typical tryptic peptides are analyzed.
=== Pharmacodynamics === Similarly to MDMA, SDMA is a serotonin–norepinephrine–dopamine releasing agent (SNDRA) and a non-selective serotonin 5-HT2 receptor agonist. However, SDMA was 11-fold more potent as a serotonin releaser, 19-fold more potent as a dopamine releaser, and 2-fold more potent as a norepinephrine releaser than MDMA in HEK293 cells in vitro. In addition, it was about twice as potent as a serotonin 5-HT2A receptor agonist, whereas it showed similar agonistic potency as MDMA at the serotonin 5-HT2B and 5-HT2C receptors. SDMA had similar activational efficacies at the serotonin 5-HT2 receptors as MDMA. Due to its greater potency as a monoamine releasing agent, SDMA may be active at lower doses or concentrations than MDMA. SDMA produced hyperlocomotion and hyperthermia in rodents with similar profiles as MDMA. However, SDMA did not produce rewarding effects in the conditioned place preference (CPP) paradigm unlike MDMA. Hence, SDMA might have reduced misuse potential compared to MDMA. As with MDMA, SDMA did not produce the head-twitch response, a behavioral proxy of psychedelic effects, in rodents, and hence may not produce hallucinogenic effects in humans. SDMA might be less cardiotoxic than MDMA due to having much greater monoamine-releasing potency but unaltered serotonin 5-HT2B receptor agonistic potency.
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.
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.