This is a working overview of heptapeptide, 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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
== History == Biomatrica was founded by scientists, Judy Müller-Cohn, PhD, and Rolf Müller, PhD, in 2004. Prior to founding Biomatrica, both had worked many years in San Diego's biotechnology industry. Müller-Cohn had previously worked at Digital Gene Technologies and Mycogen/ Dow Agrosciences, whilst Müller had worked on the HIV Core Program Project Grant at San Diego's Scripps Research Institute. Biomatrica initially developed ambient temperature storage reagents for DNA and RNA. The company's core technology was inspired by the phenomenon of anhydrobiosis, the ability of some organisms to hibernate in a desiccated state during dry periods, and then reanimate upon contact with water. Focusing on microscopic, desert-dwelling creatures called Tardigrades, which undergo anhydrobiosis for up to 120 years, Biomatrica identified how to chemically mimic the mechanism of anhydrobiosis. Following stabilization at room temperature with Biomatrica's chemical reagents, biological specimens could be rehydrated for subsequent studies with the addition of a few drops of water. Since 2012, the company has become increasingly focused on its pre-analytic collection and assay stabilization service businesses described below. In October 2018 Biomatrica was acquired by the Madison, Wisconsin-based molecular diagnostics and cancer screening company Exact Sciences Corporation for $20 million.
A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin). (NCI) Case report form
Before 2018, only registered voters aged 21 and above could vote for the members of the House of Representatives and, in most of the states, for the state legislative chamber. Voting is not mandatory. In July 2019, a bill to lower the voting age to 18 years old was officially passed. Executive power is vested in the Cabinet, led by the Prime Minister. The prime minister must be a member of the House of Representatives, who in the opinion of His Majesty the King, commands the support of a majority of members. The Cabinet is chosen from members of both houses of Parliament. The Prime Minister is both the head of cabinet and the head of government. As a result of the 2018 general election, Malaysia was governed by the Pakatan Harapan (PH) political alliance, although Prime Minister Mahathir Mohamad resigned amid a political crisis in 2020. In March 2020, the Perikatan Nasional (PN) coalition formed under Prime Minister Muhyiddin Yassin, before Muhyiddin lost majority support and was replaced by deputy Prime Minister Ismail Sabri Yaakob, a veteran politician from the United Malays National Organisation (UMNO), in August 2021. As a result of the 2022 Malaysian general election, a hung parliament was elected. Anwar Ibrahim of the PH coalition was appointed as the new Prime Minister to lead the coalition government of PH, Barisan Nasional, Gabungan Parti Sarawak, Gabungan Rakyat Sabah and several other political parties and independents. Meanwhile, PN, the only political coalition not in the coalition government, became the Opposition.
Sources: en.wikipedia.org
==== Role in myocardial growth and adaptation ==== Intracrine PTHrP has been implicated in myocardial development and adaptation to stress. It is particularly active during embryonic heart development, where it influences cardiomyocyte differentiation and growth. Additionally, under conditions of cardiac stress, such as ischemia or hypertrophy, PTHrP expression is upregulated, suggesting a protective role in maintaining myocardial function. Moreover, in vascular smooth muscle cells, intracrine PTHrP plays a dual role. While secreted PTHrP can inhibit cell proliferation via receptor-mediated pathways, intracellular PTHrP exerts a mitogenic effect, promoting vascular remodeling and adaptation in response to hemodynamic changes.
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Examples include alpha-Amanitin containing mushrooms, kava, and aflatoxin producing molds. Pyrrolizidine alkaloids, which occur in some plants, can be toxic. Green tea extract is a growing cause of liver failure due to its inclusion in more products.
== Active site == The spherical carboxypeptidase domain of the catalytic subunit has a circular indentation in the surface which is the location of the active-site groove. The base of the groove is formed by 3 β-sheets while the walls of the groove are lined with α-helices. The electron density in the middle of the groove allows a space for the zinc ion cofactor to bind. The P1' residue of the substrate is placed in a specific cavity (S1') of the active-site groove while the P1 residues and on extend into a mostly hydrophobic area of the groove (in pockets S1, S2, etc.). The scissile peptide bond is held in place with several polar interactions between protein side groups. The nitrogen atom on the C-terminal side is anchored to the nearby guanidine groups of arginine molecules. On the N-terminal side, the nitrogen atom is held by hydrogen bonds with tyrosine while the carbonyl group is held by hydrogen bonds with lysine. These interactions stretch the peptide bond and set it up for the water molecule to break it apart. While there are technically two active sites on the tetramer, one on each active subunit, only one active site can be used at a time.
Sources: en.wikipedia.org
Probable migraine describes conditions that have some characteristics of migraine, but where there is not enough evidence to diagnose it as migraine with certainty. Menstrual migraines are those that either only occur associated with a menstrual period, or occur predictably around menstrual period alongside migraines during other parts of the menstrual cycle. They typically occur in migraines without aura. They are often longer than other migraine attacks, and associated with more nausea.
== Synthesis == Immunoliposomes are created when antibodies are conjugated to liposomes. One way to do this is through covalent bonds between the antibody (or its fragment) and the lipid. Another way is through chemical modification of antibodies so they have a higher affinity for the liposome. "In general, the conjugation methodology is based on three main reactions; a reaction between activated carboxyl groups and amino groups which yields an amide bond, a reaction between pyridyl dithiols and thiols which yields disulfide bonds, and a reaction between maleimide derivatives and thiols, which yields thioether bonds."
== Health effects == Trifluoroacetic acid is a strong acid. TFA is harmful when inhaled, causes severe skin burns and is toxic for aquatic organisms even at low concentrations. Skin burns are severe, heal poorly and can be necrotic. Vapour fumes have an LC50 of 10.01 mg/L, tested on rats over 4 hours. Inhalation symptoms include mucus irritation, coughing, shortness of breath and possible formation of oedemas in the respiratory tract. Exposure damages the kidneys. TFA is also thought to be responsible for halothane-induced hepatitis. In 2024, the German Federal Institute for Risk Assessment (BfR) formally requested that the European Chemicals Agency (ECHA) reclassify TFA as "presumed" toxic to human reproduction, based on studies showing damage to animal fetuses. In June 2026, ECHA's Risk Assessment Committee (RAC) concluded that TFA fulfils the criteria for toxic to the reproduction class 1B, persistent, mobile and toxic (PMT) as well as very persistent and very mobile (vPvM). In July 2026, the European Food Safety Authority (EFSA) reduced the acceptable daily intake for TFA by 72%, from 0.05 mg/kg body weight/day down to 0.014. It also set the acute reference dose (ARfD) to 0.07 mg/kg body weight. These reductions were based on an assessment of new evidence, including changes in levels of the hormone thyroxine.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.