Everything below concerns peptidase. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-12-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
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.
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.
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.
=== Political office === The Law of June 6, 2000, requires gender parity on candidate lists for municipal, regional, senatorial, and European elections. In legislative elections, parties that do not adhere to parity are subject to financial penalties. In 2012, women represented 26.9% of the French National Assembly and 36.4% of the European Parliament. In 2017, 223 women were elected to the National Assembly, constituting 38.65% of its members. Globally, no national parliament has a female majority in both chambers. Rwanda and Bolivia have female majorities in their lower houses, though their upper houses have male majorities.
=== Respiratory === The primary cause of respiratory failure in dermatomyositis is interstitial lung disease, resulting from damage to the lung interstitium. This is particularly prominent in patients with anti–MDA5 autoantibodies, who are at high risk of developing rapidly progressive interstitial lung disease. In some people, the condition affects the diaphragm muscle, the lungs directly (through inflammation), or both. This causes difficulty breathing, and dermatomyositis is considered to be a restrictive lung disease in patients with these symptoms. Respiratory symptoms occur in about 40% of people with dermatomyositis, and in these people, the symptoms may slowly progress, contributing to increased morbidity and mortality.
=== Contraction === Neuromuscular junctions are the focal point where a motor neuron attaches to a muscle. Acetylcholine, (a neurotransmitter used in skeletal muscle contraction) is released from the axon terminal of the nerve cell when an action potential reaches the microscopic junction called a synapse. A group of chemical messengers across the synapse and stimulate the formation of electrical changes, which are produced in the muscle cell when the acetylcholine binds to receptors on its surface. Calcium is released from its storage area in the cell's sarcoplasmic reticulum. An impulse from a nerve cell causes calcium release and brings about a single, short muscle contraction called a muscle twitch. If there is a problem at the neuromuscular junction, a very prolonged contraction may occur, such as the muscle contractions that result from tetanus. Also, a loss of function at the junction can produce paralysis. Skeletal muscles are organized into hundreds of motor units, each of which involves a motor neuron, attached by a series of thin finger-like structures called axon terminals. These attach to and control discrete bundles of muscle fibers. A coordinated and fine-tuned response to a specific circumstance will involve controlling the precise number of motor units used. While individual muscle units' contract as a unit, the entire muscle can contract on a predetermined basis due to the structure of the motor unit. Motor unit coordination, balance, and control frequently come under the direction of the cerebellum of the brain.
Sources: en.wikipedia.org
In the UK (2013) DMEK is available to patients under the National Health Service at the Royal Shrewsbury Hospital, the Calderdale and Huddersfield NHS Trust, and at Worthing Hospital (Western Sussex Hospitals NHS Foundation Trust). Not all patients with diseased corneas are candidates for endothelial keratoplasty. These procedures correct corneal endothelial failure, but are not able to correct corneal scarring, thinning, or surface irregularity. There is currently limited data on long-term survival of DMEK grafts however the early indications are very positive. An upcoming systematic review will seek to compare the safety and effectiveness of DMEK versus DSAEK in people with corneal failure from Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy.
=== Calculated atomic and physical properties === Oganesson is a member of group 18, the zero-valence elements. The members of this group are usually inert to most common chemical reactions (for example, combustion) because the outer valence shell is completely filled with eight electrons. This produces a stable, minimum energy configuration in which the outer electrons are tightly bound. It is thought that similarly, oganesson has a closed outer valence shell in which its valence electrons are arranged in a 7s27p6 configuration. Consequently, some expect oganesson to have similar physical and chemical properties to other members of its group, most closely resembling the noble gas above it in the periodic table, radon. Following the periodic trend, oganesson would be expected to be slightly more reactive than radon. However, theoretical calculations have shown that it could be significantly more reactive. In addition to being far more reactive than radon, oganesson may be even more reactive than the elements flerovium and copernicium, which are heavier homologs of the more chemically active elements lead and mercury, respectively. The reason for the possible enhancement of the chemical activity of oganesson relative to radon is an energetic destabilization and a radial expansion of the last occupied 7p-subshell. More precisely, considerable spin–orbit interactions between the 7p electrons and the inert 7s electrons effectively lead to a second valence shell closing at flerovium, and a significant decrease in stabilization of the closed shell of oganesson.
== Research == In a March 2020 phase II clinical trial, Stone and colleagues suggested that phenelzine's potential effectiveness on treatment of prostate cancer. Some animal trials have shown phenelzine to potentially have neuroprotective effects.
Detention Centers run by the Assad government have been one of the most glaring human rights abuses in Syria. In 2014, the Caesar Report showed gruesome photographs smuggled out of a Syria detention center showed "the systematic killing of more than 11,000 detainees by the Syrian government in one region" during a two and a half year period of the Syria Civil War. A 2016 United Nations investigative report described the detainees in Syrian prisons as suffering under "inhuman living conditions" characterized by unclean environment, lack of sanitation and food as well as systematic torture. Following the death of prisoners in custody, fake certificates were often distributed by the government to claim that the prisoners "died of natural causes". The report further denounced Assad regime's policies of torture and summary executions in detention centres as "extermination as a crime against humanity". Syrian dungeons have been compared to the Nazi extermination camps of World War II, due to the scale of torture and mass killings going on in its prison networks. Journalist Russ Wellen reports that the "state killing machine exceeds the capacity of the system to process". In 2017 details emerged about Sednaya Prison, a military prison near Damascus operated by the Assad government. The prison has been used to hold thousands of prisoners, both civilian and government opposition. Amnesty International estimated that between 5,000 and 13,000 people were extrajudicially executed at the one prison between September 2011 and December 2015.
Sources: en.wikipedia.org
Regioselectivity: The key feature of native chemical ligation of unprotected peptides is the reversibility of the first step, the thiol(ate)–thioester exchange reaction. Native chemical ligation is exquisitely regioselective because that thiol(ate)–thioester exchange step is freely reversible in the presence of an added arylthiol catalyst. The high yields of final ligation product obtained, even in the presence of internal Cys residues in either/both segments, is the result of the irreversibility of the second (S-to-N acyl shift) amide-forming step under the reaction conditions used.
== History == Martin Freund and (Jakob) Edmund Speyer of the University of Frankfurt in Germany published the first synthesis of oxycodone from thebaine in 1916. When Freund died, in 1920, Speyer wrote his obituary for the German Chemical Society. Speyer, born to a Jewish family in Frankfurt am Main in 1878, became a victim of the Holocaust. He died on 5 May 1942, the second day of deportations from the Lodz Ghetto; his death was noted in the ghetto's chronicle. The first clinical use of the drug was documented in 1917, the year after it was first developed. It was first introduced to the U.S. market in May 1939. In early 1928, Merck introduced a combination product containing scopolamine, oxycodone, and ephedrine under the German initials for the ingredients SEE, which was later renamed Scophedal (SCOpolamine, ePHEDrine, and eukodAL) in 1942. It was last manufactured in 1987 but can be compounded. This combination is essentially an oxycodone analogue of the morphine-based "twilight sleep", with ephedrine added to reduce circulatory and respiratory effects. The drug became known as the "Miracle Drug of the 1930s" in Continental Europe and elsewhere and it was the Wehrmacht's choice for a battlefield analgesic for a time. The drug was expressly designed to provide what the patent application and package insert referred to as "very deep analgesia and profound and intense euphoria" as well as tranquillisation and anterograde amnesia useful for surgery and battlefield wounding cases.
== Daptomycin resistance == Daptomycin resistance is still uncommon, but has been increasingly reported in GRE, starting in Korea in 2005, in Europe in 2010, in Taiwan 2011, and in the United States, where nine cases have been reported from 2007 to 2011. Daptomycin resistance emerged in five of the six cases while they were treated. The mechanism of resistance is unknown. A four-million year-old strain of Paenibacillus isolated from soil samples in Lechuguilla Cave was found to be naturally resistant to daptomycin.It has been suggested that co-administration of daptomycin with at least another active antibiotic might help prevent the emergence of resistance and increase the bactericidal effect. Data from in vitro and in vivo studies suggest that a tailored approach should be used taking into account both the causative agent and the site of infection.
== Therapeutic effects == Serotonin, given orally at a dose of 100 mg, produced effects in humans including blood pressure changes, abdominal cramps, muscle aches, and a feeling of sedation. In contrast to psychedelic drugs like LSD, no hallucinogenic effects were reported. In other studies, serotonin, at low intravenous doses of 2 to 6 mg, had no effects on electroencephalogram (EEG) readings in humans. In accordance with the preceding findings, it has been stated that administration of serotonin in humans produces no psychoactive effects that cannot be attributed to anxiety by its profound peripheral adverse effects including circulatory disturbance, other autonomic effects, and vomiting. Intracerebroventricular injection of serotonin has been studied in patients with severe psychiatric conditions, but little information about its psychoactive effects is provided. It is thought that exogenous serotonin is too hydrophilic to cross the blood–brain barrier and has too poor of metabolic stability due to rapid metabolism by monoamine oxidase (MAO) such that it cannot produce drug-like central effects in humans with peripheral administration. However, close analogues of serotonin that are more lipophilic and metabolically stable, like bufotenin (N,N-dimethylserotonin), 5-MeO-DMT (N,N,O-trimethylserotonin), and 5-MeO-AMT (α,O-dimethylserotonin), among many others, are active and produce pronounced centrally mediated effects in humans.
Though rare, estimates of the prevalence of vaginal cuff dehiscence after hysterectomy are estimated and reported to be between 0.14 and 4.1% per the American College of Obstetricians and Gynecologists (ACOG). If the vaginal cuff is compromised, vaginal evisceration can occur with the small intestine protruding out through the vagina.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.