Everything below concerns heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
== In various fields == As a central goal of many individual and societal endeavors, well-being is relevant to many fields of inquiry. Grouped under the umbrella term science of well-being, some disciplines investigate the nature and components of well-being directly, while others study its causes, effects, or correlates in specific domains of life. A central motivation of academic inquiry is the belief that well-being can be improved through appropriate measures. Some of these measures focus on individual lifestyle changes. Others take the form of societal interventions to alter how economic, medical, educational, workplace, and political institutions function.
The body of a teleost is denser than water, so fish must compensate for the difference, or they will sink. A defining feature of Actinopteri (Chondrostei, Holostei and teleosts) is the swim bladder. Originally present in the last common ancestor of the teleosts, it has since been lost independently at least 30–32 times in at least 79 of 425 families of teleosts where the swim bladder is absent in one or more species. This absence is often the case in fast-swimming fishes such as the tuna and mackerel. The swim bladder helps fish adjusting their buoyancy through manipulation of gases, which allows them to stay at the current water depth, or ascend or descend without having to waste energy in swimming. In the more primitive groups like some minnows, the swim bladder is open (physostomous) to the esophagus. In fish where the swim bladder is closed (physoclistous), the gas content is controlled through the rete mirabilis, a network of blood vessels serving as a countercurrent gas exchanger between the swim bladder and the blood.
==== Insulin ==== Perhaps the most common medication administered subcutaneously is insulin. While attempts have been made since the 1920s to administer insulin orally, the large size of the molecule has made it difficult to create a formulation with absorption and predictability that comes close to subcutaneous injections of insulin. People with type 1 diabetes almost all require insulin as part of their treatment regimens, and a smaller proportion of people with type 2 diabetes do as well — with tens of millions of prescriptions per year in the United States alone. Insulin historically was injected from a vial using a syringe and needle, but may also be administered subcutaneously using devices such as injector pens or insulin pumps. An insulin pump consists of a catheter which is inserted into the subcutaneous tissue, and then secured in place to allow insulin to be administered multiple times through the same injection site.
In 1945, Yeshiva University President Samuel Belkin began planning a new medical school. Under his urging, Yeshiva's Board of Trustees negotiated with the New York State Board of Regents to expand the university's charter to grant MD degrees, finalized in December 1950. In 1951, physicist Albert Einstein wrote a letter to Belkin lauding the planned school, writing that it was "of the greatest importance to American Jewry" and would "welcome students of all creeds and races". He became an honorary chairman for the medical school campaign, alongside former First Lady Eleanor Roosevelt, New York Governor Thomas Dewey, and Richard Nixon. When approached, Einstein was initially reluctant to associate his name with the school—he had recently refused to lend his name to Brandeis University and had declined to become the second president of Israel—and instead suggested that it be named for the Jewish physician Maimonides. Two years later, at an event marking his 74th birthday, March 14, 1953, Einstein agreed to lend his name to the medical school. At the gathering—his only public appearance in 22 years at the Institute for Advanced Study—Einstein told The New York Times that "physics has favored medicine by giving civilized man confidence in the scientific method." In 1954, the college sponsored the awarding of that year's Albert Einstein Award to physicist Richard Feynman and, on his 75th birthday, gifted Einstein a Festschrift with contributions from ten Nobel laureates, Israeli Prime Minister Moshe Sharett, and President Harry S. Truman, among others.
Sources: en.wikipedia.org
== Outcomes == Overall, it appears that quality of life was found to be significantly improved for people with pelvic organ prolapse after surgical or pessary management. It can be difficult to determine success when discussing the outcomes of surgical intervention for pelvic organ prolapse due to multiple factors that can define success, such as anatomic success versus patient-reported outcome measures. Improvement of symptoms after surgery appears to be more of a measure of success for patients themselves, than does anatomic success alone. The rate of pelvic organ prolapse recurrence following surgery depends on several factors, the most significant being patient age (patients younger than 60 years have higher likelihood of recurrence), POP-Q stage (POP-Q greater than 3 has higher likelihood of recurrence), surgeon's experience performing the procedure, and prior history of pelvic surgery. Additionally, the surgical approach, for instance vaginal versus abdominal, also affects recurrence rate. The rates of reoperation following pelvic organ prolapse surgery ranges from 3.4% to 9.7%. Reoperation rates appear to be higher with transvaginal mesh repair compared to other procedures, due in part to complications such as mesh exposure.
== Reactions and uses == Vinyl sulfones are dienophiles. Subsequent to the cycloaddition to a vinyl sulfone, the phenylsulfonyl group can be removed by reduction with zinc. Vinyl sulfones are Michael acceptors. Vinyl sulfones add thiols, such as cysteine residues. This same reactive nature is responsible for their major industrial use in vinyl sulfone dyes. Phenyl vinyl sulfone has been applied to ruthenium chemistry as part of olefin metathesis reactions. Vinyl sulfone has applications to protein purification, especially when linked with mercaptoethanol.
Chamaecostus cuspidatus, common name fiery costus or spiral flag, is a species of herbaceous plant in the family Costaceae native to eastern Brazil (States of Bahia and Espírito Santo). In India, it is known as insulin plant for its purported anti-diabetic properties. Chamaecostus cuspidatus has large fleshy-looking leaves. The undersides of these large, smooth, dark green leaves have light purple shade. The leaves are spirally arranged around the stem, forming attractive, arching clumps arising from underground rootstocks. The maximum height of these plants is about two feet. The flowers are orange in color and are 1.5 in (3.8 cm) in diameter. Flowering occurs during the warm months and they appear to be cone-like heads at the tips of branches.
== Sources == Joan E. Howard, From Violence to Vision: Sacrifice in the Works of Marguerite Yourcenar (1992) Josyane Savigneau, Marguerite Yourcenar: Inventing a Life (1993). George Rousseau, Marguerite Yourcenar: A Biography (London: Haus Publishing, 2004). Judith Holland Sarnecki, Subversive Subjects: Reading Marguerite Yourcenar (2004) Giorgetto Giorgi, "Il Grand Tour e la scoperta dell’antico nel Labyrinthe du monde di Marguerite Yourcenar," in Sergio Audano, Giovanni Cipriani (ed.), Aspetti della Fortuna dell'Antico nella Cultura Europea: atti della settima giornata di studi, Sestri Levante, 19 March 2010 (Foggia: Edizioni il Castello, 2011) (Echo, 1), 99–108. Les yeux ouverts, entretiens avec Mathieu Galey (Éditions du Centurion « Les interviews », 1980). Bérengère Deprez, Marguerite Yourcenar et les États-Unis. Du nageur à la vague, Éditions Racine, 2012, 192 p. Bérengère Deprez, Marguerite Yourcenar and the United States. From Prophecy to Protest, Peter Lang, coll. « Yourcenar », 2009, 180 p. Deprez, Marguerite Yourcenar. Écriture, maternité, démiurgie, essai, Bruxelles, Archives et musée de la littérature/PIE-Peter Lang, coll. « Documents pour l’histoire des francophonies », 2003, 330 p. Donata Spadaro, Marguerite Yourcenar et l'écriture autobiographique : Le Labyrinthe du monde, bull. SIEY, no 17, décembre 1996, p. 69 à 83 Donata Spadaro, Marguerite Yourcenar e l'autobiografia (ADP, 2014) Mireille Brémond, Marguerite Yourcenar, une femme à l'Académie (Garnier, 2019);. Rémy Poignault, L'Antiquité dans l'œuvre de Marguerite Yourcenar.
== Unbinding == Substrate unbinding is influenced by various factors. Larger ligands generally stay in the active site longer, as do those with more rotatable bonds (although this may be a side effect of size). When the solvent is excluded from the active site, less flexible proteins result in longer residence times. More hydrogen bonds shielded from the solvent also decrease unbinding.
Sources: en.wikipedia.org
The first β-sheet structure was proposed by William Astbury in the 1930s. He proposed the idea of hydrogen bonding between the peptide bonds of parallel or antiparallel extended β-strands. However, Astbury did not have the necessary data on the bond geometry of the amino acids in order to build accurate models, especially since he did not then know that the peptide bond was planar. A refined version was proposed by Linus Pauling and Robert Corey in 1951. Their model incorporated the planarity of the peptide bond which they previously explained as resulting from keto-enol tautomerization.
=== Dihydrolipoyl transacetylase (E2) === The E2 subunit, or dihydrolipoyl acetyltransferase, for both prokaryotes and eukaryotes, is generally composed of three domains. The N-terminal domain (the lipoyl domain), consists of 1–3 lipoyl groups of approximately 80 amino acids each. The peripheral subunit binding domain (PSBD), serves as a selective binding site for other domains of the E1 and E3 subunits. Finally, the C-terminal (catalytic) domain catalyzes the transfer of acetyl groups and acetyl-CoA synthesis. In Gammaproteobacteria, 24 copies of E2 form the cubic core of the pyruvate dehydrogenase complex, in which 8 E2 homotrimers are located at the vertices of the cubic core particle.
=== Nanoparticles === A novel application for gel electrophoresis is the separation or characterization of metal or metal oxide nanoparticles (e.g. Au, Ag, ZnO, SiO2) regarding the size, shape, or surface chemistry of the nanoparticles. The scope is to obtain a more homogeneous sample (e.g. narrower particle size distribution), which then can be used in further products/processes (e.g. self-assembly processes). For the separation of nanoparticles within a gel, the key parameter is the ratio of the particle size to the mesh size, whereby two migration mechanisms were identified: the unrestricted mechanism, where the particle size << mesh size, and the restricted mechanism, where particle size is similar to mesh size.
According to disinformation experts and intelligence agencies, Russia spread disinformation ahead of the 2024 election to damage Biden and Democrats, boost candidates supporting isolationism, and undercut support for Ukraine aid and NATO. On September 4, 2024, the United States publicly accused Russia of interfering in the 2024 election and announced several steps to combat Russian influence including sanctions, indictments, and seizing of web domains used to spread propaganda and disinformation. U.S. intelligence agencies assessed that Russia preferred Trump to win the election, viewing him as more critical of American support for Ukraine.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。