The short version of Tuftsin fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-03 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
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.
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.
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.
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.
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.
== Calvin-Benson cycle == In the light-independent reactions (also known as the Calvin-Benson cycle), two 3-phosphoglycerate molecules are synthesized. RuBP, a 5-carbon sugar, undergoes carbon fixation, catalyzed by the rubisco enzyme, to become an unstable 6-carbon intermediate. This intermediate is then cleaved into two, separate 3-carbon molecules of 3-PGA. One of the resultant 3-PGA molecules continues through the Calvin-Benson cycle to be regenerated into RuBP while the other is reduced to form one molecule of glyceraldehyde 3-phosphate (G3P) in two steps: the phosphorylation of 3-PGA into 1,3-bisphosphoglyceric acid via the enzyme phosphoglycerate kinase (the reverse of the reaction seen in glycolysis) and the subsequent catalysis by glyceraldehyde 3-phosphate dehydrogenase into G3P. G3P eventually reacts to form the sugars such as glucose or fructose or more complex starches.
In Canada and the United States, half and half almost always refers to a light cream typically used in coffee. (See above.) The name refers to the liquid's content of half milk and half cream. It is widely available in the United States, both in individual-serving containers and in bulk. It is also used to make ice cream. Non-fat versions of the product are also available, containing corn syrup and other ingredients. This half and half can be also used to make a dirty soda. In addition to the light coffee cream, half and half can refer to other drinks in some regions of the U.S. A half and half of iced tea and lemonade is popular in the Northeastern United States. It consists of one part iced tea, sweetened, unsweetened or both, and one part lemonade served over ice. This drink is also called an Arnold Palmer, named for an American golfer, but that drink more correctly is mostly tea with one-quarter to one-third lemonade. In the Southern United States (specifically the cities of Atlanta and Houston), "half and half" may also refer to a mixture of half sweet and half unsweetened iced tea. Some coffee shops in colder climates serve a half and half drink consisting of half coffee and half hot chocolate, similar to caffè mocha. Half and half might also refer to a flavor of soda that combines the flavors of grapefruit and lemon.
Significant breast development in transgender women begins within two to three months of the start of hormone therapy and continues for up to two years or more. Breast development seems to be better in transgender women who have a higher body mass index. This indicates that weight gain in the early phases of hormone therapy may be beneficial not only for fat distribution, but for breast development. Different estrogens, such as estradiol valerate, conjugated estrogens, and ethinylestradiol, appear to produce equivalent results in terms of breast sizes in transgender women. The sudden discontinuation of estrogen therapy has been associated with onset of galactorrhea (lactation). Breast, nipple, and areolar development varies considerably depending on genetics, nutrition, age of HRT initiation, and many other factors. Development can take a couple years to nearly a decade for some. However, many transgender women report there is often a "stall" in breast growth during transition, or significant breast asymmetry. Transgender women on HRT often experience less breast development than cisgender women (especially if started after young adulthood). For this reason, many seek breast augmentation. Transgender patients opting for breast reduction are rare. Shoulder width and the size of the rib cage also play a role in the perceivable size of the breasts; both are usually larger in transgender women, causing the breasts to appear proportionally smaller.
Sources: en.wikipedia.org
Inadequate nutritional intake: Alcoholics tend to take in less than the recommended amount of thiamine. Decreased uptake of thiamine from the GI tract: Active transport of thiamine into enterocytes is disturbed during acute alcohol exposure. Liver thiamine stores are reduced due to hepatic steatosis or fibrosis. Impaired thiamine utilization: Magnesium, which is required for the binding of thiamine to thiamine-using enzymes within the cell, is also deficient due to chronic alcohol consumption. The inefficient use of any thiamine that does reach the cells will further exacerbate the thiamine deficiency. Ethanol per se inhibits thiamine transport in the gastrointestinal system and blocks phosphorylation of thiamine to its cofactor form (ThDP). Following improved nutrition and the removal of alcohol consumption, some impairments linked with thiamine deficiency are reversed, in particular poor brain functionality, although in more severe cases, Wernicke–Korsakoff syndrome leaves permanent damage. (See delirium tremens.)
=== Methionine === Biosynthesis by the transsulfuration pathway starts with aspartic acid. Relevant enzymes include aspartokinase, aspartate-semialdehyde dehydrogenase, homoserine dehydrogenase, homoserine O-transsuccinylase, cystathionine-γ-synthase, Cystathionine-β-lyase (in mammals, this step is performed by homocysteine methyltransferase or betaine—homocysteine S-methyltransferase.) Methionine biosynthesis is subject to tight regulation. The repressor protein MetJ, in cooperation with the corepressor protein S-adenosyl-methionine, mediates the repression of methionine's biosynthesis. The regulator MetR is required for MetE and MetH gene expression and functions as a transactivator of transcription for these genes. MetR transcriptional activity is regulated by homocysteine, which is the metabolic precursor of methionine. It is also known that vitamin B12 can repress MetE gene expression, which is mediated by the MetH holoenzyme.
== Example of preparing a series of standard solutions == Suppose the concentration of glutamine in an unknown sample needs to be measured. To do so, a series of standard solutions containing glutamine is prepared to create a calibration curve. A table summarizing a method for creating these solutions is shown below:
Sources: en.wikipedia.org
== Discovery and etymology == The first definitive description of a chloroplast (Chlorophyllkörnen, "grain of chlorophyll") was given by Hugo von Mohl in 1837 as discrete bodies within the green plant cell. In 1883, Andreas Franz Wilhelm Schimper named these bodies as "chloroplastids" (Chloroplastida). In 1884, Eduard Strasburger adopted the term "chloroplasts" (Chloroplasten). The word chloroplast is derived from the Greek words chloros (χλωρός), which means green, and plastes (πλάστης), which means "the one who forms".
=== Unsupported health claims === In 2010 a panel of the European Food Safety Authority examined health claims made for whey protein. For the following claims either no references were provided for the claimed effect or the provided studies did not test the claims, or reported conflicting results:
== Precision fermentation == Precision fermentation is an approach to manufacturing specific functional products which intends to minimise the production of unwanted by-products through the application of synthetic biology, particularly by generating synthetic "cell factories" with engineered genomes and metabolic pathways optimised to produce the desired compounds as efficiently as possible with the available resources. Precision fermentation of genetically modified microorganisms may be used to manufacture proteins needed for cell culture media, providing for serum-free cell culture media in the manufacturing process of cultured meat. A 2021 publication showed that photovoltaic-driven microbial protein production could use 10 times less land for an equivalent amount of protein compared to soybean cultivation. Some Food Regulatory Agencies such as the FDA do not require the labeling of precision fermented foods as GMO since they are produced by, but do not contain the genetically engineered organisms. It is unclear how regulation will be handled in EU markets, with some startups such as Formo and Those Vegan Cowboys forming the Food Fermentation Europe (FFE) alliance together with other alt-protein startups to seek regulatory approval.
=== Logos === The current logo is based on the fist and rose logo in the version created by José María Cruz Novillo for the Spanish Socialist Workers Party in 1977. The PS logo is used without official consent and agreement with PSOE.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.