This is a working overview of Pro-Gly-Pro, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-23 and is reviewed periodically as new material appears.
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.
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.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Genetically modified organism History of biotechnology An Asilomar Moment Archived 10 July 2013 at the Wayback Machine Original Asilomar Genetics Guidelines “Asilomar Conference.” Provides another summary of the Asilomar Conference. The Basics of Recombinant DNA provides an introduction to the science behind recombinant DNA. The Recombinant DNA Debate Archived 31 March 2007 at the Wayback Machine provides more details about the history of the debate surrounding the use of recombinant DNA technology. “Paul Berg: The 1980 Nobel Prize in Chemistry – Autobiography.” Provides an autobiography about Paul Berg. Science History Institute: The story of the 1975 Asilomar Conference on Recombinant DNA
== External links == Table of Nuclides. DOE Fundamentals Handbook: Nuclear Physics and Reactor Theory Vol. 1 (Archived 2017-07-31 at the Wayback Machine), Vol. 2 (Archived 2016-12-20 at the Wayback Machine). Radionuclide Basics: Uranium—US EPA NLM Hazardous Substances Databank – Uranium, Radioactive "The Miracle of U-235", Popular Mechanics, January 1941—one of the earliest articles on U-235 for the general public
== Research == A relatively recent avenue of drug research in treating depression and drug addiction is through PPARα and PPARγ activation. Both TLR4-mediated and NF-κB-mediated signalling pathways have been implicated in the development of addiction to several drugs such as opioids and cocaine, and therefore are appealing targets for pharmacotherapy. Despite a breadth of preclinical research showing potential in animal models in the treatment of drug addictions including alcohol, nicotine, cocaine, opioids and methamphetamine, the human evidence is limited with the amount of trials looking at using PPAR agonists for humans still being low; and so far (as of 2020) not being particularly promising. There are several suggested hypotheses for the poor translation from animal to human research evidence such as the potency and selectivity of PPAR ligands, sex-related variability, and species differences in the distribution and signaling of PPAR.
However, the commission concluded that an attack on Russian peacekeepers was not "a sufficient condition" to be used for self-defence by Russia and "the fact of the Georgian attack on the Russian peacekeepers’ basis could not be definitely confirmed by the mission." The commission said that Russian peacekeepers had the right to immediate, necessary and proportionate response in case of direct attack on them. However, "doubts remain whether the Russian peacekeepers were attacked in the first place," and the mission "was unable to establish whether, at the time of the alleged attacks on Russian peacekeepers’ bases, the peacekeepers had lost their protection owing to their participation in the hostilities." The commission concluded that "the expulsion of the Georgian forces from South Ossetia, and the defence of South Ossetia as a whole was not a legitimate objective", and "according to international law, the Russian military action taken as a whole was therefore neither necessary nor proportionate to protect Russian peacekeepers in South Ossetia." The commission concluded that Russia did not have the right to justify its actions as "a mere reinforcement and fulfilment of its peacekeeping mission." The commission concluded that the South Ossetian separatists "could not validly invite Russia to support them" militarily and Russian military action could not be justified as intervention in a civil war.
Sources: en.wikipedia.org
However, while salinity inhibits vesicle formation from low-diversity mixtures of fatty acids, vesicle formation from a broader, more realistic mix of fatty-acid and 1-alkanol species is more resilient. No studies have been able to experimentally demonstrate synthesis of sugars, amino acids, nucleases, nucleosides, nucleotides, or membrane-forming fatty acids under plausible vent conditions.
== Side effects == Administration of naloxone to somebody who has used opioids may cause rapid-onset opioid withdrawal. Naloxone has little to no effect if opioids are not present. In people with opioids in their system, it may cause increased sweating, nausea, restlessness, trembling, vomiting, flushing, and headache, and has in rare cases been associated with heart rhythm changes, seizures, and pulmonary edema. Naloxone has been shown to block the action of pain-lowering endorphins the body produces naturally. These endorphins likely operate on the same opioid receptors that naloxone blocks. It is capable of blocking a placebo pain-lowering response if the placebo is administered together with a hidden or blind injection of naloxone. Other studies have found that placebo alone can activate the body's μ-opioid endorphin system, delivering pain relief by the same receptor mechanism as morphine. Naloxone should be used with caution in people with cardiovascular disease as well as those who are currently taking medications that could have adverse effects on the cardiovascular system such as causing low blood pressure, fluid accumulation in the lungs (pulmonary edema), and abnormal heart rhythms. There have been reports of abrupt reversals with opioid antagonists leading to pulmonary edema and ventricular fibrillation.
== Medical uses == Omacetaxine/homoharringtonine was indicated for use as a treatment for patients with chronic myeloid leukaemia who are resistant or intolerant of tyrosine kinase inhibitors. In June 2009, results of a long-term open label Phase II study were published, which investigated the use of omacetaxine infusions in CML patients. After twelve months of treatment, about one third of patients showed a cytogenetic response. A study in patients who had failed imatinib and who had the drug resistant T315I mutation achieved cytogenetic response in 28% of patients and hematologic response in 80% of patients, according to preliminary data. Phase I studies including a small number of patients have shown benefit in treating myelodysplastic syndrome (MDS, 25 patients) and acute myelogenous leukaemia (AML, 76 patients). Patients with solid tumors did not benefit from omacetaxine.
Sources: en.wikipedia.org
== Structure == The gene coding for DPEP1 is 6 kb long and consists of ten exons and nine introns. The protein itself is made of 411 amino acid residues and is only transcribed in kidney cells. Although disulfide linkages in DPEP1 do not contribute to the enzyme’s activity, they are essential for the enzyme’s proper function because they keep the enzyme’s subunits together and attached to the renal brush border. Cysteine 261 is involved in disulfide linkage between the enzyme’s subunits, and is also located very close to both the site of the GPI-anchor and the membrane, suggesting that it is also involved in the enzyme’s linkage to the membrane. DPEP1 is also a metalloenzyme that specifically uses zinc as its cofactor. The enzyme’s typical zinc content is 1.42 ug/mg. The addition of cobalt or manganese ions cause the enzyme to take on different conformations, which suggests that the enzyme may be able to hydrolyze different dipeptides depending on which metal ions are present—aka the metal-content of one’s micronutrient intake could affect their renal dipeptidase’s ability to metabolize various dipeptides.
Insectivores which fed on unsupplemented invertebrates have been found to suffer from vitamin A deficiencies, and a study of panther chameleons (Furcifer pardalis) found vitamin A deficiency shortened life spans and reduced reproduction rates. Turkestan cockroaches are rich in vitamin B12.
CIDP is a neurological disorder caused by an injury to the protective coating of the nerves as they leave the brain. However, this was almost immediately ruled out by his physicians as testing was already done against the possibility of CIDP. Leaving the paralysis to be a rare side effect of the clinical drug, Ibrutinib Joe was taking to control his blood cancer, only he hasn't been taking the medication since a blood clot almost killed him. Dr. Lisa Sanders suggests that his regaining feeling in his toes is a result of Joe being off the medication, as it could take up to a year for the medication to fully leave his body and for the nerves to rebuild themselves. This raises the issue that if Joe stays off the medication he might be able to walk again but if he doesn't get back on he will have nothing controlling his blood cancer. Dr. Lisa Sanders later published Ann’s story on the column and awaited the response from the audience. The audience presented with many possibilities but Ann’s doctors had tested and ruled them all out except for two. The first possibility is Lyme Disease which is an infection caused by bacteria transmitted through ticks. While Ann’s symptoms are not in line with that of Lyme Disease, the disease is known for causing all kinds of strange and interesting neurological problems. The second possibility is that Ann has a Functional Neurological Disorder, where simply her body is not transmitting the correct signals.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
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.