The short version of Semax fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-31 and is reviewed periodically as new material appears.
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.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
| 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 |
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
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 whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
=== sea-sef === Sea-Mist Seasonale Seba-Gel Sebcur sebetralstat (INN) Sebizon sebriplatin (INN) secalciferol (INN) secbutabarbital (INN) seclazone (INN) secnidazole (INN) secobarbital (INN) Seconal secoverine (INN) Secran Secreflo secretin (INN) Sectral secukinumab (INN) securinine (INN) Sedapap sedecamycin (INN) Seffin
==== Anisotropic structures ==== Silver nanoparticles can be synthesized in a variety of non-spherical (anisotropic) shapes. Because silver, like other noble metals, exhibits a size and shape dependent optical effect known as localized surface plasmon resonance (LSPR) at the nanoscale, the ability to synthesize Ag nanoparticles in different shapes vastly increases the ability to tune their optical behavior. For example, the wavelength at which LSPR occurs for a nanoparticle of one morphology (e.g. a sphere) will be different if that sphere is changed into a different shape. This shape dependence allows a silver nanoparticle to experience optical enhancement at a range of different wavelengths, even by keeping the size relatively constant, just by changing its shape. This aspect can be exploited in synthesis to promote change in shape of nanoparticles through light interaction. The applications of this shape-exploited expansion of optical behavior range from developing more sensitive biosensors to increasing the longevity of textiles.
The male pilot, who was the only person on board, is taken to hospital by air ambulance. In the first statement to be released since his cancer diagnosis, Charles III thanks the public for their messages of support. 11 February – British journalist Clare Rewcastle Brown accuses Malaysia of seeking "political revenge" for her reporting after a court jailed her in absentia for criminal defamation of a Malaysian royal. 12 February Azhar Ali, the Labour Party's Rochdale by-election candidate, is suspended from the party over comments about Israel and Jewish people. He will however remain on the ballot as the Labour candidate, as it is too late to replace him under electoral law. Three apologises after three days of outages that left around 12,000 people without mobile signals and data. Child killer Colin Pitchfork will be reconsidered for parole after successfully challenging a Parole Board decision to refuse him parole on the grounds he poses too much of a risk if released from prison. 13 February A catastrophic loss of seabird numbers is reported by the RSPB and the British Trust for Ornithology, due to the spread of H5N1 bird flu. Police begin an investigation into reports of antisemitism during a performance by comedian Paul Currie at the Soho Theatre in London, which left Jewish audience members feeling "unsafe" and "threatened". Labour leader Keir Starmer insists he took "decisive action" over comments made by Rochdale by-election candidate Azhar Ali. Cosmetics retailer The Body Shop enters administration, putting more than 2,200 jobs at risk.
In the past century, there has been much research into the development of effective chiral catalysts due to its great potential in organic synthesis. In the 1960s, cyclometalation reactions including C(sp2)–H and C(sp3)–H cleavage were pioneered by Kleiman, Dubeck, Cope, and Siekman. A decade later, Shaw discovered that inorganic acetate salts promoted otherwise difficult cyclopalladations. To build off of this work, Sokolov focused on developing chiral, enantioenriched metallacyles and proposed the concerted metal-deprotonation (CMD) mechanism. Despite this foundation of discoveries, enantioselective catalysis for C–H functionalization continued to lack in efficiency oand selectivity for desired chiral product formation. In 2008, Jin-Quan Yu reported the first MPAA ligands, showcasing their use in enantioselective activation of C(sp2)–H and C(sp3)–H bonds. Initial synthesis occurred by reacting the nucleophilic amino acid in base with a highly electrophilic acyl chloride resulting in one new amide bond formation. Upon addition of acyl chloride, most resulting groups off of the nitrogen were common protecting groups used in organic synthesis, hence mono-N-protected. Taking advantage of the weak coordination of amides and carboxylates with Pd-complexes, this enantioselective catalysis requires the MPAA ligand to allow the reaction to proceed and determine the product chirality, minimizing side reactions that may occur without the ligand.
Sources: en.wikipedia.org
Low levels of glycogen branching enzyme leads to a condition known as glycogen-branching enzyme deficiency. This condition is caused by a mutation of the GBE1 gene responsible for producing the glycogen branching enzyme. Subsequently, glycogen molecules are produced with few branches, which greatly decreases the number of nonreducing ends, drastically slowing the rate at which the molecule can be synthesized or broken down. This causes low levels of muscle glycogen that is very resistant to amylase. This disease is usually seen in Quarter Horse foals and is fatal.
==== 1300–1399 ==== Concession Statements (Prescribed Information) Regulations 1993 (S.I. 1993/1300) Gipsy Encampments (City of Hereford) Order 1993 (S.I. 1993/1301) South Wales Police (Amalgamation) (Amendment) (No. 2) Order 1993 (S.I. 1993/1302) Dyfed-Powys Police (Amalgamation) (Amendment) (No. 2) Order 1993 (S.I. 1993/1303) Seed Potatoes (Fees) (Scotland) Regulations 1993 (S.I. 1993/1311) Eastwood and East Kilbride Districts (Busby) Boundaries Amendment Order 1993 (S.I. 1993/1312) Margate Pier and Harbour Revision Order 1992 (SI 1993/1313) Integrated Administration and Control System Regulations 1993 (S.I. 1993/1317) Lewisham and Southwark (London Borough Boundaries) Order 1993 (S.I. 1993/1318) Greater London and Surrey (County and London Borough Boundaries) (No.3) Order 1993 (S.I. 1993/1319) Plant Health (Great Britain) Order 1993 (S.I. 1993/1320) Health and Safety (Fees) Regulations 1993 (S.I. 1993/1321) A500 Newcastle-Under-Lyme to Nantwich Trunk Road (Basford-Hough-Shavington Bypass and Slip Road) Order 1993 (S.I. 1993/1322) A500 Newcastle-Under-Lyme to Nantwich Trunk Road (Basford-Hough-Shavington Bypass) (Detrunking) Order 1993 (S.I. 1993/1323) Post Office (Abolition of Import Restrictions) Regulations 1993 (S.I. 1993/1324) Fishing Vessels (Safety Improvements) (Grants) Scheme 1993 (S.I. 1993/1325) Insurance Companies (Cancellation) Regulations 1993 (S.I. 1993/1327) Diseases of Animals (Therapeutic Substances) (Revocation) Order 1993 (S.I. 1993/1331) Foot-and-Mouth Disease (Sera and Glandular Products) (Revocation) Order 1993 (S.I.
== Medical uses == People diagnosed with trypanosome-caused disease should be treated with an anti-trypanosomal. Treatment is based on stage, 1 or 2, and parasite, T. b. rhodesiense or T. b. gambiense. In stage 1 disease, trypanosomes are present only in the peripheral circulation. In stage 2 disease, trypanosomes have crossed the blood-brain barrier and are present in the central nervous system. The following are considerable treatment options: Melarsoprol is a treatment used during the second stage of the disease. So far, it is the only treatment available for late-stage T. b. rhodesiense. Due to high toxicity, melarsoprol is reserved only for the most dangerous cases. Other agents associated with lower toxicity levels are used during stage 1 of the disease. The approval of the nifurtimox-eflornithine combination therapy (NECT) in 2009 for the treatment of T. b. gambiense limited the use of melarsoprol to the treatment of second-stage T. b. rhodesiense. Failure rates of 27% in certain African countries have been reported. This was caused by both drug resistance and additional mechanisms that have not yet been elucidated. Resistance is likely due to transport problems associated with the P2 transporter, an adenine-adenosine transporter. Resistance can occur with point mutations within this transporter. Resistance has been present since the 1970s. In August 2024, the World Health Organization recommended fexinidazole, developed by the Drugs for Neglected Diseases initiative and partners to replace melarsoprol as the first-line treatment for sleeping sickness caused by T.
Carlos Santana told about his mescaline use in a 1989 Rolling Stone interview. Disney animator Ward Kimball described participating in a study of mescaline and peyote conducted by UCLA in the 1960s. Michael Cera used real mescaline for the movie Crystal Fairy & the Magical Cactus, as expressed in an interview. Philip K. Dick was inspired to write Flow My Tears, the Policeman Said after taking mescaline. Arthur Kleps, a psychologist turned drug legalization advocate and writer whose Neo-American Church defended use of marijuana and hallucinogens such as LSD and peyote for spiritual enlightenment and exploration, bought, in 1960, by mail from Delta Chemical Company in New York 1 g of mescaline sulfate and took 500 mg. He experienced a psychedelic trip that caused profound changes in his life and outlook. Michael Pollan has described his experiences with mescaline and San Pedro cactus.
=== NMR (1H and 13C) spectroscopy of metallocenes === Nuclear magnetic resonance (NMR) is the most applied tool in the study of metal sandwich compounds and organometallic species, giving information on nuclear structures in solution, as liquids, gases, and in the solid state. 1H NMR chemical shifts for paramagnetic organotransition-metal compounds is usually observed between 25 and 40 ppm, but this range is much more narrow for diamagnetic metallocene complexes, with chemical shifts usually observed between 3 and 7 ppm.
Sources: en.wikipedia.org
Trailer / railroad reporting marks: UPGX, UPGZ, UPOZ, UPSZ, UPWZ, UPSC, UPSU, NONZ NMFTA SCAC code: UPSS, UPSN, UPSC Until 2021, this segment also included UPS Freight which offered a variety of less than truckload ("LTL") and truckload ("TL") services to customers in North America. UPS Freight was sold to TFI International in April 2021 and was renamed TForce Freight.
Following the declaration of war against the Axis Powers, a civilian militia known as the Mexican Guerrilla Legion (Legión de Guerrilleros Mexicanos)—popularly called the "army of charros"—was organized. It was spearheaded by revolutionary Lieutenant Colonel and charro leader Antolín Jiménez Gamas, then president of the National Association of Charros, with the approval of President Ávila Camacho. Various press reports and secondary sources estimate that the Legion amassed between 100,000 and 150,000 volunteers, distributed across approximately 250 locations throughout the country. There, they held Sunday drills to practice discipline and basic defense tactics, leveraging the equestrian skills of the charros. The Legion never saw combat, and there is no evidence of any operational deployment. Its function was primarily symbolic, focused on civic-military organization and training, as part of the national preparations for a potential invasion of the Americas during the war.
== External links == Lipoprotein(a) at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Overview of all the structural information available in the PDB for UniProt: P08519 (Apolipoprotein(a)) at the PDBe-KB.
=== Rearrangement reactions === Rearrangement reactions are fragmentation reactions that form new bonds producing an intermediate structure before cleavage. One of the most studied rearrangement reaction is the McLafferty rearrangement / γ-hydrogen rearrangement. This occurs in the radical cations with unsaturated functional groups, like ketones, aldehydes, carboxylic acids, esters, amides, olefins, phenylalkanes. During this reaction, γ-hydrogen will transfer to the functional group at first and then subsequent α, β-bond cleavage of the intermediate will take place. Other rearrangement reactions include heterocyclic ring fission (HRF), benzofuran forming fission (BFF), quinone methide (QM) fission or Retro Diels-Alder (RDA).
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.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.