Everything below concerns Neurotrophic factor. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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 |
|---|---|---|
| Dry storage temperature | -20 C or below | Sealed, desiccated, protected from light |
| Solution stability | Hours to days at 2-8 C | Depends on buffer and microbial load |
| Preferred pH range | Near neutral to slightly acidic | Alkaline pH accelerates hydrolysis |
| Main degradation routes | Hydrolysis and deamidation | No cysteine or methionine in sequence |
| Identity confirmation | Electrospray mass spectrometry | Observed mass compared with 751.9 Da |
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.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
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 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.
== 1980 incident == On the evening of December 21, 1980, while celebrating Christmas with her family at their mansion, Clarendon Court, in Newport, Rhode Island, she again displayed confusion and lack of coordination. She was put to bed by her family, but in the morning she was discovered unconscious on the bathroom floor. She was taken to the hospital where it became clear that this time she had suffered severe enough brain injury to produce a persistent vegetative state. Although clinical features resembled a drug overdose, some of the laboratory evidence suggested hypoglycemia. The Court of Appeal ordered disclosure of the notes taken by the Auersperg children's attorney. These showed that Claus von Bülow did not want to terminate life support, as had been alleged. Because of the increased marital tensions between Claus and Sunny von Bülow in the fall of 1980, her children were suspicious that her brain injury was the result of foul play by him. Her two eldest children persuaded Richard H. Kuh, the former New York County District Attorney, to investigate the possibility Claus von Bülow had attempted the murder of their mother. After the gathering of evidence, Rhode Island prosecutors presented the case to a grand jury who returned an indictment, and in July 1981, he was charged with two counts of attempted murder.
Diamine oxidase (DAO), also known as amine oxidase, copper-containing, 1 (AOC1), formerly called histaminase, is an enzyme (EC 1.4.3.22) involved in the metabolism, oxidation, and inactivation of histamine and other polyamines such as putrescine or spermidine. The enzyme belongs to the amine oxidase (copper-containing) (AOC) family of amine oxidase enzymes. The enzyme is expressed in bilateria, a biological group of animals. The enzyme is encoded by the AOC1 gene. This gene is highly conserved across the bilateria group which includes mammals, birds, reptiles, fish and insects, to name a few.
Apixaban During the SAR development of apixaban there were three groups that needed to be tested to attain maximum potency and bioavailability. The first group to be tested was the non-active site as it needs to be stabilized before SAR testing on the p-methoxyphenyl group (S1 binding moiety). There are several of groups that increase the potency of the compound, mostly amides, amines and tetrazoles but also methylsulfonyl and trifluoromethyl groups. Of these groups, carboxamide has the greatest binding and had similar clotting activity as the compounds. In dog testing, this compound with a carboxamide group called 13F, showed a great pharmacokinetical profile, a low clearance and adequate half-life and volume of distribution. Due to the success of finding a stabilizing group, SAR research for S1 binding moiety (p-methoxyphenyl) was discontinued. In the S4 binding group, N-methylacetyl and lactam analogues proved to have a very high binding affinity for FXa, showed great clotting and selectivity versus other proteases. Orientation turned out to be important as N-methyl acetyl, compared to acetamide, had a 300 fold lower binding ability to FXa due to unfavorable planarity close to the S4 region binding site.
== Mechanism == Riboflavin is converted into catalytically active cofactors FAD and FMN by the actions of riboflavin kinase EC 2.7.1.26, which converts it into FMN, and FAD synthetase EC 2.7.7.2, which adenylates FMN to FAD. The RFK module phosphorylates the riboflavin substrate and converts it into FMN, which is then released from the module. This reaction is dependent on an ATP molecule stabilized by an Mg2+ ion, which causes only a single phosphate group to leave the ATP and bond to riboflavin. The released FMN then joins to the N-terminal FMNAT module and is adenylated, with the adenylyl group of ATP attaching to the phosphate group on FMN and the diphosphate group leaving. ATP + riboflavin ⇌ ADP + FMN ATP + FMN ⇌ diphosphate + FAD
=== Caffeine === One tablespoonful (5 grams) of dry unsweetened cocoa powder has 12.1 mg of caffeine and a 25-g single serving of dark chocolate has 22.4 mg of caffeine. This is much less than the amount found in coffee, of which a single 7 oz. (200 ml) serving may contain 80–175 mg of caffeine, though studies have shown psychoactive effects in caffeine doses as low as 9 mg, and a dose as low as 12.5 mg was shown to have effects on cognitive performance.
Sources: en.wikipedia.org
=== Liberal Leaders in the House of Commons === Henry John Temple, 3rd Viscount Palmerston (1859–1865) William Ewart Gladstone (1865–1875) Spencer Cavendish, 8th Duke of Devonshire (1875–1880) William Gladstone (1880–1894) Sir William Harcourt (1894–1898) Henry Campbell-Bannerman (1899–1908) H. H. Asquith (1908–1916)
Sir Frederick Gowland Hopkins (20 June 1861 – 16 May 1947) was an English biochemist who was awarded the Nobel Prize in Physiology or Medicine in 1929, with Christiaan Eijkman, for the discovery of vitamins. He also discovered the amino acid tryptophan, in 1901. He was President of the Royal Society from 1930 to 1935.
=== Phosphorylation-dependent ubiquitylation === The interplay between ubiquitylation and phosphorylation has been an ongoing research interest since phosphorylation often serves as a marker where ubiquitylation leads to degradation. Moreover, ubiquitylation can also act to turn on/off the kinase activity of a protein. The critical role of phosphorylation is largely underscored in the activation and removal of autoinhibition in the Cbl protein. Cbl is an E3 ubiquitin ligase with a RING finger domain that interacts with its tyrosine kinase binding (TKB) domain, preventing interaction of the RING domain with an E2 ubiquitin-conjugating enzyme. This intramolecular interaction is an autoinhibition regulation that prevents its role as a negative regulator of various growth factors and tyrosine kinase signaling and T-cell activation. Phosphorylation of Y363 relieves the autoinhibition and enhances binding to E2. Mutations that render the Cbl protein dysfunctional due to the loss of its ligase/tumor suppressor function and maintenance of its positive signaling/oncogenic function have been shown to cause the development of cancer.
=== Livestock and crop predation === A limitation of food sources in early spring and wild berry and nut crop failures in summer may contribute to bears regularly feeding from human-based food sources. These bears often eat crops, especially during autumn hyperphagia when natural foods are scarce. Favored crops include apples, oats and corn. American black bears can do extensive damage in areas of the northwestern United States by stripping the bark from trees and feeding on the cambium. Livestock depredations occur mostly in spring. Although they occasionally hunt adult cattle and horses, they seem to prefer smaller prey such as sheep, goats, pigs and young calves. They usually kill by biting the neck and shoulders, though they may break the neck or back of the prey with blows with the paws. Evidence of a bear attack includes claw marks and is often found on the neck, back and shoulders of larger animals. Surplus killing of sheep and goats is common. American black bears have been known to frighten livestock herds over cliffs, causing injuries and death to many animals; whether this is intentional is not known. Occasionally bears kill pets, especially domestic dogs, which are most prone to harass a bear. It is not recommended to use unleashed dogs to deter bear attacks. Although large, aggressive dogs can sometimes cause a bear to run, if pressed, angry bears often turn the tables and end up chasing the dogs in return. A bear in pursuit of a pet dog can threaten both canid and human lives.
== Structure and function == PPO is listed as a morpheein, a protein that can form two or more different homo-oligomers (morpheein forms), but must come apart and change shape to convert between forms. It exists as a monomer, trimer, tetramer, octamer or dodecamer, creating multiple functions. In plants, PPO is a plastidic enzyme with unclear synthesis and function. In functional chloroplasts, it may be involved in oxygen chemistry like mediation of pseudocyclic photophosphorylation. Enzyme nomenclature differentiates between monophenol oxidase enzymes (tyrosinases) and o-diphenol:oxygen oxidoreductase enzymes (catechol oxidases). The substrate preference of tyrosinases and catechol oxidases is controlled by the amino acids around the two copper ions in the active site.
Sources: en.wikipedia.org
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.
Hydrolysis of peptide bonds and deamidation of arginine and proline residues are the main degradation routes. Alkaline pH and higher temperatures accelerate both processes. Buffered, near-neutral solutions stored cold generally degrade more slowly than unbuffered ones.
Reverse-phase chromatography gives the clearest single view of related impurities and truncated sequences. Mass spectrometry then confirms that the main peak carries the expected mass. Neither test detects enantiomeric impurities, which require a separate chiral assay.
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.