Semax comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-10-19. Numbers and descriptions here follow the published literature rather than marketing material.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
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。
A nuclear localization signal (NLS) is a target peptide that directs proteins to the nucleus and is often a unit consisting of five basic, positively charged amino acids. The NLS normally is located anywhere on the peptide chain. A nuclear export signal (NES) is a target peptide that directs proteins from the nucleus back to the cytosol. It often consists of several hydrophobic amino acids (often leucine) interspaced by 2-3 other amino acids. Many proteins are known to constantly shuttle between the cytosol and nucleus and these contain both NESs and NLSs.
Researchers have cultured it in order to understand the biology of the eukaryotic cell and ultimately human biology in great detail. Other species of yeasts, such as Candida albicans, are opportunistic pathogens and can cause infections in humans. Yeasts have recently been used to generate electricity in microbial fuel cells and to produce ethanol for the biofuel industry. Yeasts do not form a single taxonomic or phylogenetic grouping. The term "yeast" is often taken as a synonym for Saccharomyces cerevisiae, but the phylogenetic diversity of yeasts is shown by their placement in two separate phyla: the Ascomycota and the Basidiomycota. The budding yeasts, or "true yeasts", are classified in the order Saccharomycetales, within the phylum Ascomycota.
Sisters went on to achieve critical recognition, being considered among the best American films of the decade by critic Robin Wood, as well as one of the most important films in Kidder's career by film critic G. Allen Johnson. In 1974, she starred in the slasher film Black Christmas, for which she won a Canadian Film Award for Best Actress, followed by a role as a prostitute in the Terrence Malick–scripted The Gravy Train (1974). She received another Canadian Film Award for Best Actress for her performance in the war drama A Quiet Day in Belfast (1974). Also in 1974, Kidder made her directorial debut with a 50-minute short film produced for the American Film Institute, titled Again. The film follows a woman who pastes photographs of her former lovers on her wall, continuously searching for "Mr. Right".
== History == Source distantly originates from the GoldSrc engine, itself a heavily modified version of John Carmack's Quake engine with some code from the Quake II engine. Carmack commented on his blog in 2004 that "there are still bits of early Quake code in Half-Life 2". Valve employee Erik Johnson explained the engine's nomenclature on the Valve Developer Community:
=== Pubic hair === Pubic hair is often the second noticeable change in puberty, usually within a few months of thelarche. It is referred to as pubarche. The pubic hairs are usually visible first along the labia. The first few hairs are described as Tanner stage 2. Stage 3 is usually reached within another 6–12 months, when the hairs are too numerous to count and appear on the pubic mound as well. By stage 4, the pubic hairs densely fill the "pubic triangle". Stage 5 refers to spread of pubic hair to the thighs and sometimes as abdominal hair upward towards the navel. In about 15% of females, the earliest pubic hair appears before breast development begins.
Sources: en.wikipedia.org
== Limitations == FFF does not work for small molecules, because of their fast diffusion. For an effective separation, the sample has to be concentrated very close to the accumulation wall (a distance less than 10 μm), which requires the drift velocity caused by the force field to be two orders of magnitude higher compared to the diffusion coefficient. The maximum field strength which can be generated in an FFF channel determines the lower size range of separation. For current instrumentation this is approximately 1 nm. Although FFF is an extremely versatile technique, there is no "one size fits all" method for all applications. Different FFF methods need specialized instrumentation. Currently only the so-called asymmetric flow field-flow fractionation (AF4) has gained widespread use. Other methods like centrifugal, thermal or electrical FFF still have a niche existence. FFF behaves differently from column chromatography and can be counter-intuitive for HPLC or SEC users. Understanding of the working principle of FFF is vital for a successful application of the method.
=== Linkage isomerization === Linkage isomerism occurs with ligands with more than one donor atom, known as ambidentate ligands. For example, nitrite can coordinate through O or N. One pair of nitrite linkage isomers have structures (NH3)5CoNO2+2 (nitro isomer) and (NH3)5CoONO2+ (nitrito isomer).
=== Mechanism of action === Mifamurtide is a fully synthetic derivative of muramyl dipeptide (MDP), the smallest naturally occurring immune stimulatory component of cell walls from Mycobacterium species. It has similar immunostimulatory effects as natural MDP with the advantage of a longer half-life in plasma. NOD2 is a pattern recognition receptor which is found in several kinds of white blood cells, mainly monocytes and macrophages. It recognises muramyl dipeptide, a component of the cell wall of bacteria. Mifamurtide simulates a bacterial infection by binding to NOD2, activating white cells. This results in an increased production of TNF-α, interleukin 1, interleukin 6, interleukin 8, interleukin 12, and other cytokines, as well as ICAM-1. The activated white cells attack cancer cells, but not, at least in vitro, other cells.
== Career == Before getting involved with the original Counter-Strike, Jess Cliffe was a very active gaming website designer. The earliest known gaming website he founded was Jedi Knight Multiplayer Addon Group (JKMAG) which he founded in December 1997. After around a year of maintaining the website, he moved on to start the website Action Quake2 Map Depot. It was during the time he was involved with this site that he got to know Marcelo Dilay and Minh Le, as Dilay and Le were part of the team developing Action Quake 2. Around January 1999, Cliffe also founded the website Silo X devoted to Half-Life maps. After graduating, Cliffe took a job with Valve, where he was employed as a game designer, 3D artist and level designer. However, he was suspended from Valve in early 2018 due to being arrested.
Juan Zarate, who served as Deputy National Security Advisor for Combating Terrorism from 2005 to 2009, noted that "the severity and extreme disruption of a novel coronavirus will likely spur the imagination of the most creative and dangerous groups and individuals to reconsider bioterrorist attacks."
Sources: en.wikipedia.org
He is also related to Leonard Wolfson, Baron Wolfson, Miel de Botton and Janet Wolfson de Botton, Trustee of Tate and Chairman of the Council of Tate Modern and appointed Commander of the Most Excellent Order of the British Empire (CBE) in 2006 and elevated to Dame Commander of the Order of the British Empire (DBE) in the 2013 Birthday Honours for charitable services to the arts. Caryl Brahms writer Julius Braunthal (1891–1972) was an Austrian Jewish historian, magazine editor, and political activist; Secretary of the Socialist International from 1951 to 1956; wrote three volume History of the International, first published in German between 1961 and 1971. David Bret biographer, broadcaster and chansonnier (French-born; Jewish father) Jacob Bronowski (18 January 1908 – 22 August 1974) Polish-British mathematician, philosopher, academic and author of more than eighteen scholarly books, focusing on William Blake, magic and evolution; is best known for developing a humanistic approach to science, and as the presenter and writer of the 1973 BBC television documentary series, and accompanying book The Ascent of Man, which led to his regard as "one of the world's most celebrated intellectuals". Anita Brookner (16 July 1928 – 10 March 2016) of Polish Jewish ancestry, novelist and art historian; Slade Professor of Fine Art at the University of Cambridge from 1967 to 1968; first woman to hold this visiting professorship; awarded Booker–McConnell Prize for her novel Hotel du Lac. Sam Bourne novelist pseudonym of Jonathan Freedland.
Anisocytosis is a medical term meaning that a patient's red blood cells are of unequal size. This is commonly found in anemia and other blood conditions. False diagnostic flagging may be triggered on a complete blood count by an elevated WBC count, agglutinated RBCs, RBC fragments, giant platelets or platelet clumps due to anisocytosis. In addition, it is a characteristic feature of bovine blood. The red cell distribution width (RDW) is a measurement of anisocytosis and is calculated as a coefficient of variation of the distribution of RBC volumes divided by the mean corpuscular volume (MCV).
A similar role has been suggested for clays, though this speculation has not been supported through experimental evidence. The prebiotic synthesis of peptides from simpler molecules such as CO, NH3 and C, skipping the step of amino acid formation, is also very efficient.
== Treatment == Treatment is indicated when the so-called table-top test is positive. With this test, the person places their hand on a table. If the hand lies completely flat on the table, the test is considered negative. If the hand cannot be placed completely flat on the table, leaving a space between the table and a part of the hand as big as the diameter of a ballpoint pen, the test is considered positive and surgery or other treatment may be indicated. Additionally, finger joints may become fixed and rigid. There are several types of treatment, with some hands needing repeated treatment. The main categories listed by the International Dupuytren Society in order of stage of disease are radiation therapy, needle aponeurotomy (NA), collagenase injection, and hand surgery. As of 2016 the evidence on the efficacy of radiation therapy was considered inadequate in quantity and quality, and difficult to interpret because of uncertainty about the natural history of Dupuytren's disease. Needle aponeurotomy is most effective for Stages I and II, covering 6–90 degrees of deformation of the finger. However, it is also used at other stages. Collagenase injection is likewise most effective for Stages I and II. However, it is also used at other stages. Hand surgery is effective at stage I to stage IV. Use of a splint to keep treated fingers straight following various forms of treatment, typically at all times for some days, then at nighttime for some weeks, is usual.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.