This is a working overview of Enkephalinase, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
24 June NASA publishes images showing an unexpected and unexplained double crater from what is thought to be the first time human space debris – likely by a spent rocket body – unintentionally hit the lunar surface on 4 March. Early 2022 monkeypox outbreak research:A study reports phylogenomic characterization of the first monkeypox (MP) virus outbreak genome sequences, finding the "presumably slow-evolving" DNA virus has evolved roughly 6–12-fold more mutations than one would expect and 15 SNP mutations since the beginning of the outbreak. The WHO announces that MP is not yet a global public health emergency but a cause for deep concern (25 June). Early overviews and reviews, including about current knowledge about MP prevention and treatment, are published. Scientists are investigating circulating lineages (and potential variants) of the MP virus and compare them to the African endemic lineages. A preprint suggests that cases "where a small fraction of individuals have disproportionately large numbers of partners, can explain the sustained growth of monkeypox cases among the MSM population" (13 June). The MP incubation period is estimated to be 8.5 days on average and up to 21 days (16 June). The 3D-folded structures of the whole proteome of the current DNA virus are predicted, which may be useful for the development of (better or updated) vaccines and drugs (28 June). A study indicates MP contaminated surfaces within hospitals and households could be infectious (30 June).
== N == N-acetylaspartate (NAA) A molecule found predominantly in neurons, often measured via magnetic resonance spectroscopy as a marker of neuronal health and density. Narcolepsy A neurological disorder characterized by excessive daytime sleepiness, sudden sleep attacks, and sometimes cataplexy. It involves dysfunction in the brain's regulation of sleep–wake cycles. Nasal cavity The air passageway behind the nose that houses the olfactory epithelium, which contains sensory neurons responsible for detecting odors. Neocortex The largest part of the cerebral cortex, involved in higher-order brain functions such as sensory perception, motor commands, reasoning, and language. Neologism A newly coined word or expression. In neuropsychology, may refer to nonsensical or made-up words produced by individuals with certain types of aphasia. Neostriatum A subdivision of the basal ganglia comprising the caudate nucleus and putamen. It is involved in motor control and reward processing. Neural crest A group of embryonic cells that gives rise to various structures, including peripheral neurons, glia, and parts of the face and skull. Neural oscillation Rhythmic or repetitive electrical activity in the central nervous system, often observed as brain waves in EEG recordings. Neural plasticity The ability of the nervous system to change its structure and function in response to experience, injury, or development. Neural stem cell A self-renewing progenitor cell capable of generating neurons and glial cells.
Bard (1933–2024), American chemist known for development of the scanning electrochemical microscope, Wolf Prize in Chemistry Vincenzo Barone (born 1952), Italian chemist working in theoretical and computational chemistry Denise Barthomeuf (1934-2004), French chemist working on zeolites Neil Bartlett (1932–2008), English/Canadian/American chemist known for creating the first noble-gas compound Sir Derek Barton (1918–1998), 1969 Nobel Prize in Chemistry for “contributions to the development of the concept of conformation and its application in chemistry"
According to the 1996 edition of Vogel's Textbook, yields close to 100% are called quantitative, yields above 90% are called excellent, yields above 80% are very good, yields above 70% are good, yields above 50% are fair, and yields below 40% are called poor. In their 2002 publication, Petrucci, Harwood, and Herring wrote that Vogel's Textbook names were arbitrary, and not universally accepted, and depending on the nature of the reaction in question, these expectations may be unrealistically high. Yields may appear to be 100% or above when products are impure, as the measured weight of the product will include the weight of any impurities. In their 2016 laboratory manual, Experimental Organic Chemistry, the authors described the "reaction yield" or "absolute yield" of a chemical reaction as the "amount of pure and dry product yielded in a reaction". They wrote that knowing the stoichiometry of a chemical reaction—the numbers and types of atoms in the reactants and products, in a balanced equation "make it possible to compare different elements through stoichiometric factors." Ratios obtained by these quantitative relationships are useful in data analysis.
=== Doping === As of 2007, it was widely reported that tetracosactide had been used as an illegal performance-enhancing drug by professional cyclists. It is known to be used as a doping agent to increase the secretion of glucocorticoids by adrenal glands.
Sources: en.wikipedia.org
immunofluorescence (IF) A family of laboratory techniques in which a particular antigen or antibody is conjugated to a fluorescent dye and then allowed to bind specifically to its complementary antibody or antigen, if any exists, in a culture vessel, tissue section or smear, hybridization probe, membrane blot, or any other context. The presence or absence of the complement and its specific location(s) can be visualized by illuminating the sample with ultraviolet light and observing the fluorescence from the conjugated fluorophore, often under a microscope.
=== Coup in Cambodia === In the spring of 1970 Kissinger was under immense strain as several of his aides were planning to resign to protest the upcoming U.S invasion of Cambodia, and his liberal friends from Harvard were pressuring him to resign as well while Nixon was all for more belligerence. Much of Kissinger's staff were deeply opposed to the invasion of Cambodia. Kissinger asked one of his aides, William Watts, to be in charge of National Security Council staffing for the coming invasion. Watts refused, saying he was opposed to the invasion on moral grounds, causing Kissinger to shout: "Your views represent the cowardice of the Eastern Establishment!" Watts resigned on the spot. As Watts was writing his resignation letter, Kissinger's deputy, Alexander Haig, appeared to tell him on behalf of Kissinger: "You've just had an order from your commander in chief. You can't quit". Watts replied: "Fuck you Al! I just did". Kissinger received a phone call from Nixon and his best friend, Charles "Bebe" Rebozo, who both sounded very drunk; Nixon began the call and then handed the phone to Rebozo who said: "The President wants you to know if this doesn't work, Henry, it's your ass". On 30 April 1970, the United States invaded Cambodia, which Nixon announced in a television address that Kissinger contemptuously called "vintage Nixon" because of his overblown rhetoric. At the time, Nixon was seen as recklessly escalating the war, and in early May 1970, the largest protests ever against the Vietnam War took place.
Pictures of scarification in Africa – Features by Jean-Michel Clajot, Belgian photographer and Saï Sotima Tchantipo Doctor Anthropology Extensive Scarification Article – Features different scarification techniques and advice BME Website – Chronicles the current and historical body modifications world internationally Scarification – entry in BME Encyclopedia
=== First Supply Chain Management Certification === The term Supply Chain Management (SCM) was coined in the early eighties (1982) by Booz Allen Consultant, Keith Oliver, but remained only a buzzword for many years. The holistic concept of a cross-functional set of processes aimed to fulfill the customer's needs, started to make sense to companies, consultants and academics in the early nineties. It was until the decade's end, when technology enabled Business Process Integration throughout each company and extended to other companies, that the term SCM was widely adopted. SCM finally grew to become normal science in the first decade of the millennium. ISCEA's founding members identified the need of a professional SCM certification organization and developed the Certified Supply Chain Manager (CSCM) certification program. It was the first certification program developed by ISCEA and was launched simultaneously with ISCEA's initial website in early 2003. There are other professional knowledge certifying bodies currently offering SCM certification. Some of them founded many years before ISCEA. But their SCM certification programs were released after ISCEA's CSCM:
Prozac had sales in excess of $1 billion per year in the late 1990s. Barr Laboratories of the U.S. obtained exclusivity for all of the approved dosage forms (10 mg, 20 mg) except one (40 mg), which was obtained by Reddy's. Lilly had numerous other patents surrounding the drug compound and had already enjoyed a long period of patent protection. The case to allow generic sales was heard twice by the Federal Circuit Court, and Reddy's won both hearings. Reddy's generated nearly $70 million in revenue during the initial six-month exclusivity period. With such high returns at stake, Reddy's was gambling on the success of the litigation; failure to win the case could have cost them millions of dollars, depending on the length of the trial. The fluoxetine marketing success was followed by the American launch of Reddy's house-branded ibuprofen tablets in 400, 600 and 800 mg strengths, in January 2003. Direct marketing under the Reddy's brand name represented a significant step in the company's efforts to build a strong and sustainable US generic business. It was the first step in building Reddy's fully-fledged distribution network in the US market. In 2015, Dr. Reddy's Laboratories bought the established brands of Belgian drugmaker UCB SA in South Asia for ₹8 billion ($128.38 million). Dr. Reddy's Laboratories also signed a licensing pact with XenoPort for their experimental treatment to treat plaque psoriasis. As per the agreement, Dr. Reddy's will be granted exclusive US rights to develop and commercialise XP23829 for all indications for an upfront payment of $47.5 million.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.