The short version of Pro-Gly-Pro fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-20. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
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.
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 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.
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.
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.
C-reactive protein (CRP) is an annular (ring-shaped) pentameric protein found in blood plasma, whose circulating concentration rises in response to inflammation. It is an acute-phase protein of hepatic origin that increases following interleukin-6 secretion by macrophages and T cells. Its physiological role is to bind to lysophosphatidylcholine expressed on the surface of dead or dying cells (and some types of bacteria) in order to activate the complement system via C1q. CRP is synthesized by the liver in response to factors released by macrophages, T cells and fat cells (adipocytes). It is a member of the pentraxin family of proteins. It is not related to C-peptide (insulin) or protein C (blood coagulation). C-reactive protein was the first pattern recognition receptor (PRR) to be identified.
=== Air quality analysis === In Fig. 3 a mass spectrum of air inside a laboratory (obtained with a time-of-flight (TOF) based PTR-MS instrument), is shown. The peaks on m/z 19, 37 and 55 (and their isotopes) represent the reagent ions (H3O+) and their clusters. On m/z 30 and 32 NO+ and O2+, which are both impurities originating from the ion source, appear. All other peaks correspond to compounds present in typical laboratory air (e.g. high intensity of protonated acetone on m/z 59). If one takes into account that virtually all peaks visible in Fig. 3 are in fact double, triple or multiple peaks (isobaric compounds) it becomes obvious that for PTR-MS instruments selectivity is at least as important as sensitivity, especially when complex samples / compositions are analyzed. One methods for improving the selectivity is high mass resolution. When the PTR source is coupled to a high resolution mass spectrometer isobaric compounds can be distinguished and substances can be identified via their exact mass. Some PTR-MS instruments are, despite the lack of a mass filter between the ion source and the drift tube, capable of switching the reagent ions (e.g. to NO+ or O2+). With the additional information obtained by using different reagent ions a much higher level of selectivity can be reached, e.g. some isomeric molecules can be distinguished.
Bismuth subcitrate potassium is a bismuth salt used in combination with antibiotics and a proton pump inhibitor for the treatment of Helicobacter pylori infections. A fixed-dose combination with the antibiotics metronidazole and tetracycline is sold under the trade name Pylera.
Sources: en.wikipedia.org
=== Home sleep test (HST) / home sleep apnea test (HSAT) === Sleep apnea can also be diagnosed using an in-home testing kit. The main advantage is that these record in the usual sleep environment and thus are more representative of their natural sleep than staying overnight at a lab. Home sleep testing is more accessible and less expensive than polysomnography due to long waiting periods for in-lab tests.
== Signs and symptoms == In their early stages, soft-tissue sarcomas usually do not cause symptoms. Because soft tissue is relatively elastic, tumors can grow rather large, pushing aside normal tissue, before they are felt or cause any problems. The first noticeable symptom is usually a painless lump or swelling. As the tumor grows, it may cause other symptoms, such as pain or soreness, as it presses against nearby nerves and muscles. If in the abdomen it can cause abdominal pains commonly mistaken for menstrual cramps, indigestion, or cause constipation.
== Signs and symptoms == The symptoms of rhabdomyolysis depend on its severity and whether kidney failure develops. Milder forms may not cause any muscle symptoms, and the diagnosis is based on abnormal blood tests in the context of other problems. More severe rhabdomyolysis is characterized by muscle pain, tenderness, weakness, and swelling of the affected muscles. If the swelling is very rapid, as may happen with a crush injury after someone is released from under heavy collapsed debris, the movement of fluid from the bloodstream into damaged muscle may cause low blood pressure and shock. Other symptoms are nonspecific and result either from the consequences of muscle tissue breakdown or from the condition that originally led to the muscle breakdown. Release of the components of muscle tissue into the bloodstream causes electrolyte disturbances, which can lead to nausea, vomiting, confusion, coma or abnormal heart rate and rhythm. The urine may be dark, often described as "tea-colored", due to the presence of myoglobin. Damage to the kidneys may give rise to decreased or absent urine production, usually 12 to 24 hours after the initial muscle damage. Swelling of damaged muscle occasionally leads to compartment syndrome—compression of surrounding tissues, such as nerves and blood vessels, in the same fascial compartment—leading to the loss of blood supply and damage or loss of function in the part(s) of the body supplied by these structures. Symptoms of this complication include pain or reduced sensation in the affected limb.
Sources: en.wikipedia.org
Optical: To improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. The most common indication in this category is pseudophakic bullous keratopathy, followed by keratoconus, corneal degeneration, keratoglobus and dystrophy, as well as scarring due to keratitis and trauma. Tectonic/reconstructive: To preserve corneal anatomy and integrity in patients with stromal thinning and descemetoceles, or to reconstruct the anatomy of the eye, e.g. after corneal perforation. Therapeutic: To remove inflamed corneal tissue unresponsive to treatment by antibiotics or anti-virals. Cosmetic: To improve the appearance of patients with corneal scars that have given a whitish or opaque hue to the cornea.
The tournament will be hosted by whoever wins the regular season title. Right now, either James Madison or Old Dominion will host the tournament, depending on their regular season outcomes. Last updated: October 31, 2011Source: NMN Athletics Colonial Athletic Association 2011 CAA Men's Soccer Tournament 2011 NCAA Division I men's soccer season 2011 NCAA Division I Men's Soccer Championship
Marcey Lynn Waters is the Glen H. Elder Jr., Distinguished Professor of Chemistry at the University of North Carolina, Chapel Hill (UNC-CH). She is an organic chemist whose research is at the interface of chemical biology and supramolecular chemistry. Waters has received multiple awards for research, teaching, and advocating for women in science. She served as president of the American Peptide Society (APS) from 2017 to 2019. Waters graduated from the University of California, San Diego with a degree in chemistry in 1992. While an undergraduate, she worked with Prof. Charles L. Perrin studying fundamental aspects of aromaticity. Waters entered the University of Chicago for her doctoral degree in chemistry, working with Prof. William D. Wulff studying the mechanism for the Wulff-Dotz benzannulation reaction between Fischer carbene complexes. and alkynes. Walters graduated from Chicago in 1997 with a PhD in chemistry. She was an NIH postdoctoral fellow in Prof. Ronald Breslow's group from 1997 to 1999, where she worked on dinuclear metalloenzyme mimics and antiaromaticity.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
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.