A practical reference on tuftsin: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-01-14 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
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.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
== PNA translation from other nucleic acids == Several labs have reported sequence-specific polymerization of peptide nucleic acids from DNA or RNA templates. Liu and coworkers used these polymerization methods to evolve functional PNAs with the ability to fold into three-dimensional structures, similar to proteins, aptamers and ribozymes.
Morphine is converted into heroin by a simple chemical reaction with acetic anhydride, followed by purification. Especially in Mexican production, opium may be converted directly to "black tar heroin" in a simplified procedure. This form predominates in the U.S. west of the Mississippi. Relative to other preparations of heroin, it has been associated with a dramatically decreased rate of HIV transmission among intravenous drug users (4 percent in Los Angeles vs. 40 percent in New York) due to technical requirements of injection, although it is also associated with greater risk of venous sclerosis and necrotizing fasciitis.
=== As a drug target === Given its prominent role in both diabetes and CVD, RAGE is a promising therapeutic target. Preclinical and clinical studies are exploring RAGE antagonism to treat these conditions. Blocking RAGE signaling, either through pharmacological inhibitors or soluble decoy receptors like sRAGE, has shown potential in reducing vascular complications in diabetic patients. These strategies may offer new ways to manage the chronic inflammation and oxidative stress that drive both diabetic complications and cardiovascular disease progression RAGE's role in diabetes and cardiovascular disease highlights the importance of its signaling pathway in mediating chronic inflammation and vascular damage. Targeting RAGE could offer a promising approach to mitigating the burden of these diseases, particularly in patients with diabetes, where current therapies may fall short in preventing cardiovascular complications.
== Epidemiology == NAION is the most frequently diagnosed sudden optic nerve disease in adults over 50, predominantly affecting Caucasians, with variable rates reported in Asian populations, and affecting males more than females. Presentation can vary, but patients typically report painless visual loss upon waking up in the morning or after a nap. While the exact number of cases is unclear, estimates suggest thousands of new cases occur annually in the United States alone. Associations with other health issues like diabetes and sleep apnea have been observed, though links with arteriosclerosis and cerebrovascular diseases are not typically found with NAION.
=== Micronutrient metabolism === Riboflavin, FMN, and FAD are involved in the metabolism of niacin, vitamin B6, and folate. The synthesis of the niacin-containing coenzymes, NAD and NADP, from tryptophan involves the FAD-dependent enzyme, kynurenine 3-monooxygenase. Dietary deficiency of riboflavin can decrease the production of NAD and NADP, thereby promoting niacin deficiency. Conversion of vitamin B6 to its coenzyme, pyridoxal 5'-phosphate, involves the enzyme, pyridoxine 5'-phosphate oxidase, which requires FMN. An enzyme involved in folate metabolism, 5,10-methylenetetrahydrofolate reductase, requires FAD to form the amino acid, methionine, from homocysteine. Riboflavin deficiency appears to impair the metabolism of the dietary mineral, iron, which is essential to the production of hemoglobin and red blood cells. Alleviating riboflavin deficiency in people who are deficient in both riboflavin and iron improves the effectiveness of iron supplementation for treating iron-deficiency anemia.
Sources: en.wikipedia.org
=== Desired target effect === Identical drugs can produce different results depending on the route of administration. For example, some drugs are not significantly absorbed into the bloodstream from the gastrointestinal tract and their action after enteral administration is therefore different from that after parenteral administration. This can be illustrated by the action of naloxone (Narcan), an antagonist of opiates such as morphine. Naloxone counteracts opiate action in the central nervous system when given intravenously and is therefore used in the treatment of opiate overdose. The same drug, when swallowed, acts exclusively on the bowels; it is here used to treat constipation under opiate pain therapy and does not affect the pain-reducing effect of the opiate.
In size, malonylation (three carbons) is bulkier than acetylation (two) but smaller than succinylation (four) and glutarylation (five). As a result, such acidic acyl modifications, as discussed for malonylation and succinylation, are expected to exert a greater impact than acetylation at the same lysine site. Each modification arises from the corresponding acyl-CoA derivative. Malonyl‑CoA is produced in cytosol and mitochondria by acetyl‑CoA carboxylase (ACC) and, in mitochondria, also by acyl-CoA synthetase family member 3 (ACSF3); succinyl‑CoA stems from the TCA cycle and amino acid catabolism; glutaryl‑CoA from amino acid catabolism; and methylmalonyl‑CoA from amino acid and odd‑chain fatty acid metabolism, which accumulates in vitamin B12 deficiency and methylmalonic acidemias. Malonyl‑CoA is far less reactive toward proteins than succinyl‑CoA or glutaryl‑CoA because, like acetyl‑CoA, its shorter carbon chain cannot support the intramolecular catalysis needed to form a reactive cyclic anhydride intermediate, which in turn enables modification over a broader pH range. Malonyl, succinyl, and glutaryl groups are removed by Sirtuin 5 (SIRT5), which shows little activity toward acetylation.
==== Brain ==== KORs are widely distributed throughout the brain. The claustrum represents the brain region with the highest density of KOR expression. Other CNS regions expressing moderate to high KOR densities include the prefrontal cortex, periaqueductal gray, dorsal raphe nuclei (dorsal), ventral tegmental area, substantia nigra, dorsal striatum (putamen, caudate), ventral striatum (nucleus accumbens, olfactory tubercle), amygdala, bed nucleus of the stria terminalis, hippocampus (pyramidal and molecular layers, granular cell layer of the dentate gyrus), hypothalamus, thalamus (centromedian, paraventricular, and centrolateral nuclei), locus coeruleus, spinal trigeminal nucleus, parabrachial nucleus, and solitary nucleus. Positron emission tomography (PET) imaging studies with the KOR-selective radioligand [11C]GR-103545 in non-human primates showed high binding potential (BPND > 1.3) in the pituitary gland, followed by insula, claustrum, and orbitofrontal cortex, with moderate binding (BPND 0.9–1.3) in nucleus accumbens, amygdala, and hippocampus. [3H]bremazocine binding showed elevated densities along the ventral edge of the nucleus accumbens and ventral putamen regions. There is evidence that distribution and/or function of this receptor may differ between sexes.
18-Methoxycoronaridine (18-MC; developmental code name MM-110), also known as zolunicant (INNTooltip International Nonproprietary Name), is a derivative of ibogaine invented in 1996 by the research team around the pharmacologist Stanley D. Glick from the Albany Medical College and the chemists Upul K. Bandarage and Martin E. Kuehne from the University of Vermont. 18-MC was originally developed by Savant HWP and later acquired by MindMed in 2019 for development as a treatment for opioid use disorder. A Phase 1 trial in healthy volunteers was completed in 2022 with favorable safety and tolerability. Due to strategic reprioritization, MindMed discontinued active development of MM-110 in 2023 and has been seeking non-dilutive funding or partners to potentially restart the program; as of 2025 the program remains shelved. A separate Phase 2 trial in Brazil for cutaneous leishmaniasis (initiated 2017) has unknown status with no published results.
Sources: en.wikipedia.org
Gardner, who was vice president, had political ambitions and left the company when he was elected to the United States House of Representatives in 1966. The 1964 menu included hamburger for 15 cents, cheeseburgers for 20 cents, french fries for 10 cents, apple turnovers for 15 cents, milk for 12 cents, coffee for 10 cents, soft drinks for 10 cents, and milkshakes (chocolate, strawberry, vanilla) for 20 cents. Strawberry milkshakes were created from vanilla by addition of a berry syrup which had to be mixed with a spindle.
== Pharmacology == Sunobinop has nanomolar affinity (Ki) and efficacy (EC50) at human recombinant nociceptin/orphanin-FQ peptide (NOP) receptors. It has a high degree of functional selectivity for the NOP receptor. Sunobinop is a low affinity antagonist at human mu and kappa opioid receptors, and is a low affinity weak partial agonist at human delta opioid receptors.
According to Thomson's model, all of the alpha particles should have passed through with negligible deflection. Rutherford deduced that the positive charge of the atom is not distributed throughout the atom's volume as Thomson believed, but is concentrated in a tiny nucleus at the center. This nucleus also carries most of the atom's mass. Only such an intense concentration of charge, anchored by its high mass, could produce an electric field strong enough to deflect the alpha particles as observed. Rutherford's model, being supported primarily by scattering data unfamiliar to many scientists, did not catch on until Niels Bohr joined Rutherford's lab and developed a new model for the electrons. Rutherford model predicted that the scattering of alpha particles would be proportional to the square of the atomic charge. Geiger and Marsden's based their analysis on setting the charge to half of the atomic weight of the foil's material (gold, aluminium, etc.). Amateur physicist Antonius van den Broek noted that there was a more precise relation between the charge and the element's numeric sequence in the order of atomic weights. The sequence number came be called the atomic number and it replaced atomic weight in organizing the periodic table.
Sources: en.wikipedia.org
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.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.