If you have been reading about tuftsin and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-08-10. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
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.
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.
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.
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.
Affimers are recombinant proteins. As they are manufactured using recombinant bacterial production processes, the batch-to-batch consistency for Affimers is improved compared to polyclonal antibodies, overcoming some of the issues of reproducibility and security of supply. These synthetic antibodies were engineered to be stable, non-toxic, biologically neutral and contain no post-translational modifications or disulfide bridges. Two separate loop sequences, incorporating a total of 12 to 36 amino acids, form the target interaction surface so interaction surfaces can range form 650–1000 Å. The large interaction surface results allows binding to target proteins. Affimer technology has been commercialised and developed by Avacta, which is developing these affinity reagents as tools for diagnostics and as biotherapeutics.
The Magnetic Levitation Method (MLM) is a technique for growing 3D cell cultures. In this approach, cells are treated with magnetic nanoparticles and exposed to spatially varying magnetic fields produced by neodymium magnetic drivers. The process causes cells to levitate to the air-liquid interface within a standard petri dish. The magnetic nanoparticle assemblies consist of magnetic iron oxide nanoparticles, gold nanoparticles, and cell-adhesive peptide sequences. This method can be applied to cultures with five hundred to millions of cells and is adaptable for use in single-dish systems as well as high-throughput, low-volume systems. Magnetized cells can also be used as building blocks for magnetic 3D bioprinting.
==== CYP2D6 inhibition ==== Doxepin has been identified as an inhibitor of CYP2D6 in vivo in a study of human patients being treated with 75 to 250 mg/day for depression. While it significantly altered metabolic ratios for sparteine and its metabolites, doxepin did not convert any of the patients to a different metabolizer phenotype (e.g., extensive to intermediate or poor). Nonetheless, inhibition of CYP2D6 by doxepin could be of clinical importance.
tmax: Time to achieve a maximum plasma concentration t1/2: Biological half-life Atomoxetine The pharmacokinetics of atomoxetine are similar in children, teenagers and adults. Pharmacokinetics of atomoxetine has not been studied in children younger than 6 years old. Pharmacokinetic studies have shown that atomoxetine capsules and oral solutions are equivalent. Atomoxetine is very water soluble so it absorbed rapidly and completely after oral administration. Atomoxetine reaches Cmax 1 to 2 hours after administration. The bioavailability of atomoxetine after oral administration is 63-94%, it is dependent on individual differences in the first-pass metabolism. Atomoxetine is widely distributed and is highly (98%) bound to plasma proteins, mainly albumin. The volume of distribution for atomoxetine is 0.85 L/kg, with limited partitioning into red blood cells. Atomoxetine is mainly metabolized by the cytochrome P4502D6 (CYP2D6) enzyme system. The main metabolite formed is 4-hydroxyatomoxetine, which glucuronate rapidly. 4-hydroxyatomoxetine is equivalent to atomoxetine but is much lower in plasma. The mean elimination half-life of atomoxetine after oral administration is 3.6 hours in individuals in extensive metabolism and 21 hours in those with a slow metabolism. Atomoxetine is excreted mainly as 4-hydroxyatomoxetin-O-glucoronide with urine. Reboxetine If 4 mg of reboxetine is taken orally by a healthy adult, the peak levels can be about 130 ng/mL and are achieved within 2 hours after administration.
Sources: en.wikipedia.org
The caloric content of breastmilk is reflective of the caloric requirements of the infant, increasing steadily after 12 months. The caloric content of breastmilk in the first 12 months of breastfeeding is approximated to be 58-72 Calories/100mL. Comparatively, the caloric content after 48 months is approximately 83-129 Calories/100mL. When a mother has her full milk supply and is feeding her infant, the first milk to be expressed is called the foremilk. Foremilk is typically thinner and less rich in calories. The hindmilk that follows is rich in calories and fat. If the mother is not deficient in vitamins, breast milk normally supplies the baby's needs, except for Vitamin D. The CDC, National Health Service (UK), Canadian Paediatric Society, the American Academy of Pediatrics, and the American Academy of Family Physicians all agree that breast milk alone does not provide infants with an adequate amount of Vitamin D, thus they advise parents to supplement their infants with 400 IU Vitamin D daily. Providing this quantity of Vitamin D to breastfeeding infants has been shown to reduce rates of Vitamin D insufficiency (defined as 25-OH vitamin D < 50 nmol/L). However, there was insufficient evidence in the most recent Cochrane Review to determine if this quantity reduced rates of Vitamin D deficiency (defined as 25-OH vitamin D < 30 nmol/L) or rickets. Term infants typically do not need iron supplementation. Delaying cord clamping at birth for at least one minute improves the infants' iron status for the first year.
=== Pediatrics === In a meta analysis of 17 studies, PCT had a sensitivity of 85% and a specificity of 54% in diagnosing sepsis in neonates and children. The PCT cut off used was between 2-2.5 ng/mL. In children presenting with fever without an apparent source, a PCT level of .5 ng/mL had a sensitivity of 82% and specificity of 86%. At a 5 ng/mL value, the sensitivity and specificity were 61% and 94%. PCT can help the clinical decision making while identifying invasive bacterial infection in children with unexplained fever. PCT levels correlate with the degree of illness in pediatric patients with sepsis or urinary tract infections making it effective as a prognostic lab value in these patients.
Although cadmium usually has an oxidation state of +2, it also exists in the +1 state. Cadmium and its congeners are not always considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. Cadmium burns in air to form brown amorphous cadmium oxide (CdO); the crystalline form of this compound is a dark red which changes color when heated, similar to zinc oxide. Hydrochloric acid, sulfuric acid, and nitric acid dissolve cadmium by forming cadmium chloride (CdCl2), cadmium sulfate (CdSO4), and cadmium nitrate (Cd(NO3)2) respectively. The oxidation state +1 can be produced by dissolving cadmium in a mixture of cadmium chloride and aluminium chloride, forming the Cd2+2 cation as cadmium(I) tetrachloroaluminate, which is similar to the Hg2+2 cation in mercury(I) chloride.
Sources: en.wikipedia.org
Although most yeasts have only a single actin gene, higher eukaryotes, in general, express several isoforms of actin encoded by a family of related genes. Mammals have at least six actin isoforms coded by separate genes, which are divided into three classes – alpha, beta, and gamma – according to their isoelectric points. In general, alpha actins are found in muscle (α-skeletal, α-aortic smooth, α-cardiac), whereas beta and gamma isoforms are prominent in non-muscle cells (β-cytoplasmic, γ1-cytoplasmic, γ2-enteric smooth). Although the amino acid sequences and in vitro properties of the isoforms are highly similar, these isoforms cannot completely substitute for one another in vivo. Plants contains more than 60 actin genes and pseudogenes. The typical actin gene has an approximately 100-nucleotide 5' UTR, a 1200-nucleotide translated region, and a 200-nucleotide 3' UTR. The majority of actin genes are interrupted by introns, with up to six introns in any of 19 well-characterised locations. The high conservation of the family makes actin the favoured model for studies comparing the introns-early and introns-late models of intron evolution.
=== Synthesis === A variety of synthetic routes to β-hydroxy β-methylbutyric acid have been developed. The first reported chemical syntheses approached HMB by oxidation of alkene, vicinal diol, and alcohol precursors:
== Dosage regimen == The dosage in patients without severe renal impairment is 50 μg/kg subcutaneously once a day either abdominal, in thigh, or hip. Most patients will be able to self-administer the drug after appropriate training. Patients with severe renal impairment should receive only 25 μg/kg daily. The first dose should be given 6 to 24 hours after completion of chemotherapy. Dosing should be continued until platelet counts reach at least 50,000 cells. Usually, one course of Neumega encompasses 10 to 21 days. The drug should be discontinued at least 2 days before starting the next chemotherapy cycle.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.