Everything below concerns Enkephalinase. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-09. Numbers and descriptions here follow the published literature rather than marketing material.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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 |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
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.
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.
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
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.
== Release == PYY is found in L cells in the mucosa of gastrointestinal tract, especially in ileum and colon. Also, a small amount of PYY, about 1-10%, is found in the esophagus, stomach, duodenum and jejunum. PYY concentration in the circulation increases postprandially (after food ingestion) and decreases by fasting. In addition, PYY is produced by a discrete population of neurons in the brainstem, specifically localized to the gigantocellular reticular nucleus of the medulla oblongata. C. R. Gustavsen et al. had found PYY-producing cells located in the islets of Langerhans in rats. They were observed either alone or co-localized with glucagon or PP. PYY is released by the L-cells of the gastrointestinal tract following food intake, and there are two main endogenous forms: PYY1-36 and PYY3-36. PYY1-36 is rapidly processed by the enzyme DPP4 to the 34-amino acid peptide PYY3-36. DPP4 hydrolyses PYY and removes the first two amino acids, tyrosine and proline, at the N-terminal, which changes the receptor selectivity. As a result of this, PYY3-36 has a high selectivity for the Y2-receptor, compared to PYY1-36 which has selectivity for the Y1, Y2, and Y5 receptors. It is thought that the Y1 receptor requires both the C-terminus and N-terminus for recognition, binding and then subsequent activation. The Y2 receptor is thought to have a smaller receptor site and also only requires the C-terminus for recognition. This could explain the reduced affinity for PYY3-36 on any other Y receptor other than Y2.
== Overdose == Acute overdosage is often manifested by vomiting, lethargy, ataxia, tachycardia, and seizures. Plasma, serum, or blood concentrations of paroxetine may be measured to monitor therapeutic administration, confirm a diagnosis of poisoning in hospitalized patients or to aid in the medicolegal investigation of fatalities. Plasma paroxetine concentrations are generally in a range of 40–400 μg/L in persons receiving daily therapeutic doses and 200–2,000 μg/L in poisoned patients. Postmortem blood levels have ranged from 1–4 mg/L in acute lethal overdose situations. Along with the other SSRIs, sertraline and fluoxetine, paroxetine is considered a low-risk drug in cases of overdose.
Remdesivir is a protide (prodrug of nucleotide) able to diffuse into cells, where it is converted to GS-441524 monophosphate via the actions of esterases (CES1 and CTSA) and a phosphoamidase (HINT1); this in turn is further phosphorylated to its active metabolite triphosphate by nucleoside-phosphate kinases. This pathway of bioactivation is meant to occur intracellularly, but a substantial amount of remdesivir is prematurely hydrolyzed in plasma, with GS-441524 being the major metabolite in plasma, and the only metabolite remaining two hours after dosing.
Regulation In B. subtilis, this pathway is regulated by a two-component system: DesK and DesR. DesK is a membrane-associated kinase and DesR is a transcriptional regulator of the des gene. The regulation responds to temperature; when there is a drop in temperature, this gene is upregulated. Unsaturated fatty acids increase the fluidity of the membrane and stabilize it under lower temperatures. DesK is the sensor protein that, when there is a decrease in temperature, will autophosphorylate. DesK-P will transfer its phosphoryl group to DesR. Two DesR-P proteins will dimerize and bind to the DNA promoters of the des gene and recruit RNA polymerase to begin transcription. Pseudomonas aeruginosa In general, both anaerobic and aerobic unsaturated fatty acid synthesis will not occur within the same system, however Pseudomonas aeruginosa and Vibrio ABE-1 are exceptions. While P. aeruginosa undergoes primarily anaerobic desaturation, it also undergoes two aerobic pathways. One pathway utilizes a Δ9-desaturase (DesA) that catalyzes a double bond formation in membrane lipids. Another pathway uses two proteins, DesC and DesB, together to act as a Δ9-desaturase, which inserts a double bond into a saturated fatty acid-CoA molecule. This second pathway is regulated by repressor protein DesT. DesT is also a repressor of fabAB expression for anaerobic desaturation when in presence of exogenous unsaturated fatty acids. This functions to coordinate the expression of the two pathways within the organism.
Sources: en.wikipedia.org
=== Collecting === A self-professed bibliophile, Szathmary began collecting books shortly after arriving in America, which culminated in a collection of 45,000 books and culinary materials. Szathmary was raised in a bookish family that had a standing account with a book dealer since the 1790s. Szathmary's collection comprises culinary books and handwritten manuscripts, a menu collection, Hungarian collections, and letters from Hungarian composer Franz Liszt. Szathmary stored his collection in the upstairs rooms of The Bakery restaurant building in thirty-one rooms in seventeen apartments. This immense collection has been divided and donated to various universities and institutions: The Szathmary Culinary Collection at the University of Iowa, the Szathmary Hungarica Collection at the University of Chicago, a collection of personal papers at DePaul University in Chicago, a collection of letters to and from Franz Liszt donated to the Liszt collection at Boston University and a 400,000-item culinary arts collection including menus which became the foundation for the Culinary Archives and Museum at Johnson & Wales University in Providence, Rhode Island.
International Chemical Safety Card 0275 (gas) International Chemical Safety Card 0695 (solution) NIOSH Pocket Guide to Chemical Hazards. "#0293". National Institute for Occupational Safety and Health (NIOSH). Entry for "Formaldehyde" on the Australian National Pollutant Inventory Formaldehyde from ChemSub Online Prevention guide—Formaldehyde in the Workplace (PDF) from the IRSST Formaldehyde from the National Institute for Occupational Safety and Health IPCS Health and Safety Guide 57: Formaldehyde IPCS Environmental Health Criteria 89: Formaldehyde SIDS Initial Assessment Report for Formaldehyde from the Organisation for Economic Co-operation and Development (OECD) Formaldehyde in the Pesticide Properties DataBase (PPDB)
AAV-mediated gene transfer of the full-length Mybpc3 (defined as "gene replacement") dose-dependently prevents the development of cardiac hypertrophy and dysfunction in homozygous Mybpc3-targeted knock-in mice. The dose-dependent expression of exogenous Mybpc3 was associated with the down-regulation of endogenous mutant Mybpc3. Additional expression of a sarcomeric protein is expected to replace partially or completely the endogenous protein level in the sarcomere, as it has been shown in transgenic mice expressing sarcomeric proteins.
Sources: en.wikipedia.org
Inputs include clinical tests (cold ethyl chloride, EPT, hot-gutta percha, palpation), radiographic analysis (peri-apical and/or cone-beam computed tomography) and others. Thermal tests are subjective, and are therefore performed the compromised tooth and the adjacent and contralateral teeth, allowing the patient to compare them. Normal healthy teeth are used as a baseline for diagnoses. Key characteristics of symptomatic irreversible pulpitis include:
=== Other activities === High has been on NIH study sections for hematology and for therapeutic approaches to genetic disease. She was on the National Heart, Lung and Blood Advisory Council, on the NIH Clinical Center Advisory Council, and on the Board of Scientific Counsellors for the National Eye Institute. She did a four year term on the FDA Advisory Committee on Cell, Tissue and Gene Therapy (2001–2005) and was the President of the American Society of Gene and Cell Therapy (2004–2005).
=== Sudetenland as part of Germany === The Sudetenland was initially put under military administration, with General Wilhelm Keitel as military governor. On 14 April 1939, the annexed territories were divided, with the southern parts being incorporated into the neighbouring Reichsgaue of Niederdonau, Oberdonau and Bayerische Ostmark.
May 21, 1992: Decree concerning the responsibilities of the Secretary of State for Women's Rights and Consumer Affairs. July 22, 1992: Law reforming the provisions of the Penal Code relating to the repression of crimes and offenses against persons. November 2, 1992: Law concerning abuse of authority in sexual matters in work relationships and amending the Labour Code and the Code of Criminal Procedure. January 8, 1992: Law amending the Civil Code concerning civil status, family, and children's rights, and establishing the family affairs judge. January 27, 1993: Law concerning various social measures, notably establishing the offense of obstructing abortion and decriminalizing self-induced abortion. April 8, 1993: Decree concerning the responsibilities of the Minister of State, Minister of Social Affairs, Health, and the City. July 22, 1993: Law reforming nationality law. August 2, 1993: Law concerning the control of immigration and the conditions of entry, reception, and residence of foreigners in France. April 21, 1994: Discussion on the possibility of quotas and potential gender parity in the exercise of responsibilities, particularly political ones. July 15, 1994: Law concerning the family. July 29, 1994: Law concerning respect for the human body. July 29, 1994: Law concerning the donation and use of elements and products of the human body, medically assisted procreation, and prenatal diagnosis. June 1, 1995: Decree concerning the responsibilities of the Minister for Intergenerational Solidarity. October 18, 1995: Creation of the Observatory for Gender Parity.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
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.