tuftsin raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-09-26 and is reviewed periodically as new material appears.
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.
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.
| 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 |
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.
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 not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
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.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
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.
Viscous mucus secreted by glands in the cervix presents a unique environment for drug delivery. Due to its ability to retain substances and slowly release them, it holds potential to be used as a natural, noninvasive drug delivery system. The mucus can act as a reservoir for compounds that destroy pathogens. However, the cervical mucus also presents a barrier to drug delivery as it can be really thick, making it difficult to permeate the mucus barrier. The mechanisms for penetration and bioactivity of the cervical mucus must be understood to utilize the mucus’s potential as a drug delivery system. Due to the changes in viscosity and water content of the mucus during the stages of the menstrual cycle, this poses a particularly complex consideration. For example, the cervical mucus will be thicker when a woman is not ovulating in order to prevent sperm from being able to penetrate the mucus barrier, which also in turn makes in more difficult for penetration of drug delivery systems.
By continuously scanning a surface, such as tissue section, nano-DESI can be used for imaging. By carefully choosing the experimental conditions, such as the nano-DESI solvent, additives, and the ionization mode (positive or negative) we can map the distribution of a wide variety of complex molecules on different surfaces. A few examples to mention are proteins, lipids, small metabolites, drugs or even the distribution of endogenous alkali metals. Nano-DESI has been applied for localized analysis of complex molecules and imaging of tissue sections, microbial communities and environmental samples. By decreasing the inner diameter of the primary and secondary capillaries, spatial resolution can be decreased to 20x20 μm or even smaller facilitating the analysis of individual cells. This way even various proteoforms can be measured in single cells as well as global and spatial metabolomics.
That evidence bolstered the hypothesis that heavier elements are the product of nucleosynthesis in stars. More recently, such observations provided evidence that elements are formed by neutron capture in the s-process. Since that discovery, there have been many searches in terrestrial materials for natural sources of technetium. In 1962, technetium-99 was isolated and identified in pitchblende from the Belgian Congo in very small quantities (about 0.2 ng/kg), where it originates as a spontaneous fission product of uranium-238. The natural nuclear fission reactor in Oklo contains evidence that significant amounts of technetium-99 were produced and have since decayed into ruthenium-99.
== Cancer == Hsp70 is overexpressed in melanoma and underexpressed in renal cell cancer. In breast cancer cell line (MCF7) has been found that not only Hsp90 interacted with estrogen receptor alpha (ERα) but also Hsp70-1 and Hsc70 interacted with ERα too. Given the role of heat shock proteins as an ancient defense system for stabilizing cells and eliminating old and damaged cells, this system has been co-opted by cancer cells to promote their growth. Increased Hsp70 in particular has been shown to inhibit apoptosis of cancer cells, and increased Hsp70 has been shown to be associated with or directly induce endometrial, lung, colon, prostate, and breast cancer, as well as leukemia. Hsp70 in cancer cells may be responsible for tumorigenesis and tumor progression by providing resistance to chemotherapy. Inhibition of Hsp70 has been shown to reduce the size of tumors and can cause their complete regression. Hsp70/Hsp90 is a particularly attractive target for therapeutics, because it is regulated by the inhibition of its ATPase activity, while other HSPs are regulated by nucleotides. Several inhibitors have been designed for Hsp70 that are currently in clinical trials, though as of now HSP90 inhibitors have been more successful. In addition, Hsp70 has been shown to be a regulator of the immune system, activating the immune system as an antigen. Thus, tumor-derived Hsp70 has been suggested as a potential vaccine or avenue to target for immunotherapy.
=== Gold Cup runners-up and the 2001 Copa América (2000–2001) === Colombia made their first appearance at the CONCACAF Gold Cup as invited guests in 2000, beating Jamaica 1–0 through Gonzalo Martínez and losing 2–0 to Honduras in a three-team group, both matches played at the Miami Orange Bowl. In the quarter-final on 19 February they twice came from behind against the hosts the United States — Faustino Asprilla cancelling out Brian McBride and Gerardo Bedoya equalising in the 81st minute after Chris Armas had scored — to draw 2–2 after extra time, then won the shootout 2–1 in a sequence in which six of the nine attempts failed. A 2–1 semi-final win over Peru at Qualcomm Stadium followed, an own goal by Marcial Salazar and a Víctor Bonilla strike putting Colombia through before a crowd of 3,402. In the final at the Los Angeles Memorial Coliseum on 27 February, Canada won 2–0 through a Jason de Vos header in first-half stoppage time and a Carlo Corazzin penalty, before 6,197 spectators.
Sources: en.wikipedia.org
. The carbon-carbon bond lengths of benzene are 140 picometers (pm) long, which are greater than a C=C double bond (135 pm) but shorter than a C-C single bond (147 pm). In terms of bonding, the molecular orbital (MO) description involves three bonding pi-MOs. A valence bond description involves a superposition of resonance structures. Its considerable stability and distinctive chemical properties are manifested in the phenomenon of aromaticity. To reflect the delocalized nature of the bonding, benzene is often depicted with a circle inside a hexagonal arrangement of carbon atoms.
== Side effects == Among antibiotic drugs, meropenem is relatively safe. The most common adverse effects are diarrhea (4.8%), nausea and vomiting (3.6%), injection-site inflammation (2.4%), headache (2.3%), rash (1.9%) and thrombophlebitis (0.9%). Many of these adverse effects were observed in severely ill individuals already taking many medications including vancomycin. Meropenem has a reduced potential for seizures in comparison with imipenem. Several cases of severe hypokalemia have been reported.
§: Only ionizable residues have a meaningful pKa. Values for Asp, Cys, Glu, His, Lys & Tyr were determined using the amino acid residue placed centrally in an alanine pentapeptide. The value for Arg is from Pace et al. (2009). The value for Sec is from Byun & Kang (2011). Note: the pKa value of an amino-acid residue in a small peptide is typically slightly different when it is inside a protein. Protein pKa calculations are sometimes used to calculate the change in the pKa value of an amino-acid residue in this situation.
=== Phase 1 === Dexmedetomidine (BXCL-501; Igalmi; KalmPen) – α2-adrenergic receptor agonist [21] ENX-205 – dopamine D2 and D3 receptor antagonist and serotonin 5-HT1A and 5-HT2A receptor agonist [22] (R)-Midomafetamine ((R)-MDMA; EMP-01) – serotonin–norepinephrine releasing agent, weak serotonin 5-HT2 receptor agonist, and entactogen [23] Mirodenafil (AR-1001) – phosphodiesterase PDE5 inhibitor [24]
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.