synthetic heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-14 and is reviewed periodically as new material appears.
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.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
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.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
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。
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Clorazepate, sold under the brand name Tranxene among others, is a benzodiazepine medication. It possesses anxiolytic, anticonvulsant, sedative, hypnotic, and skeletal muscle relaxant properties. Clorazepate is an unusually long-lasting benzodiazepine and serves as a prodrug for the equally long-lasting desmethyldiazepam, which is rapidly produced as an active metabolite. Desmethyldiazepam is responsible for most of the therapeutic effects of clorazepate. It was patented in 1965 and approved for medical use in 1967.
From 1967 to 1993, almost all paclitaxel produced was derived from bark of the Pacific yew, Taxus brevifolia, the harvesting of which kills the tree in the process. The processes used were descendants of the original isolation method of Monroe Wall and Mansukh Wani; by 1987, the U.S. National Cancer Institute (NCI) had contracted Hauser Chemical Research of Boulder, Colorado, to handle bark on the scale needed for phase II and III trials. While both the size of the wild population of the Pacific yew and the magnitude of the eventual demand for paclitaxel were uncertain, it was clear that an alternative, sustainable source of the natural product would be needed. Initial attempts to broaden its sourcing used needles from the tree, or material from other related Taxus species, including cultivated ones, but these attempts were challenged by the relatively low and often highly variable yields obtained. Early in the 1990s, coincident with increased sensitivity to the ecology of the forests of the Pacific Northwest, paclitaxel was extracted on a clinically useful scale from these sources.
== Function == SLC1A2 / EAAT2 is a member of a family of the solute carrier family of proteins. The membrane-bound protein is the principal transporter that clears the excitatory neurotransmitter glutamate from the extracellular space at synapses in the central nervous system. Glutamate clearance is necessary for proper synaptic activation and to prevent neuronal damage from excessive activation of glutamate receptors. EAAT2 is responsible for over 90% of glutamate reuptake within the brain.
=== Subacute === Studies in rats showed decreased weight, and gastric, intestinal, and renal function changes, while repetitive doses lead to neurotoxicity. Reproductive toxicity in males was also reported. A NOAEL in rodents was observed at 43 μg/kg body weight.
Sources: en.wikipedia.org
Refers to the practices and procedures used for the prevention, treatment, or relief of symptoms of a diseases or abnormal conditions. This term may also refer to a legal drug used for the same purpose. (NCI) Meta-analysis
"The soy foods movement began in small pockets of the counterculture, notably the Tennessee commune named simply The Farm, but by the mid-1970s a vegetarian revival helped it gain momentum and even popular awareness through books such as The Book of Tofu." Although practically unseen in 1900, by 2000 soybean plantings covered more than 70 million acres, second only to corn, and it became America's largest cash crop. In 2021, 87,195,000 acres were planted, with the largest acreage in the states of Illinois, Iowa, and Minnesota.
boiling flask Also Florence flask. A type of flask, usually made of glass, with a large round body, long neck, and flat bottom, designed especially for heating, boiling, and distilling liquids and to make swirling easy. See also round-bottom flask.
== External links == The MEROPS online database for peptidases and their inhibitors: S01.223 Acrosin at the U.S. National Library of Medicine Medical Subject Headings (MeSH) This article incorporates text from the United States National Library of Medicine, which is in the public domain.
In January 1949, President Truman, responding to advice from staff who had worked with IIAA, proposed a globalized version of the program as the fourth element of his overall foreign policy – "Point IV". The purpose of the program was to provide technical knowledge to aid the growth of underdeveloped countries around the world. After a lengthy debate, Congress approved the Point Four Program in 1950 and the Technical Cooperation Administration (TCA) was established within the Department of State in September 1950 to administer it. After an initial attempt to operate in the mode of the old Interdepartmental Committee and to merely coordinate programs of other agencies (such as IIAA), TCA adopted an integrated implementation mechanism in November 1951. In an approach that was greatly expanded after 1953, some early technical assistance projects were implemented by U.S. universities under contract to TCA. University project staff in some cases helped perform administrative functions in TCA missions that were in the process of being set up.
Sources: en.wikipedia.org
=== Mechanisms of resistance === A major mechanism of resistance against piperacillin-tazobactam is Gram-negative bacteria producing β-lactamases. Other currently known mechanisms include mutations in the active site of penicillin-binding proteins, changes in membrane efflux, or bacteria permeability. Some enzymes, such as extended-spectrum β-lactamase (ESBL) have evolved from narrow-spectrum β-lactamases due to genetic mutations, increasing their capabilities to hydrolyze much broader spectrum penicillin. Due to prior conflicting reports on the drug's affinity with ESBL-producing bacteria, piperacillin-tazobactam treatment for such is not recommended. Antibiotic resistance occurs sporadically, conferred by the continuous use of piperacillin-tazobactam in situations where it may prove to be ineffective, leading to cases where plasmid-mediated β-lactamases are being produced in bacteria that do not naturally produce it. Some Gram-positive bacteria penicillin-binding proteins such as Enterococcus faecium (PBP-5) or Staphylococcus aureus (PBP-2a) are intrinsically antibiotic resistant, consisting of relatively low affinity with piperacillin and therefore high resistance to piperacillin-tazobactam. Furthermore, mutations in penicillin-binding proteins cause fluctuations in piperacillin affinity, whereas Streptococcus pneumoniae (PBP-2b) autolytic response is significantly reduced due to decreased affinity with piperacillin.
=== Continued employment by the Astros === As part of a personal services contract Bagwell signed with the Astros, he served as a coach in spring training of 2007. On July 11, 2010, the Astros hired Bagwell to be their hitting coach, replacing Sean Berry. At the time of the switch, the Astros had the second-worst average (.237) in the majors and the worst OBP (.295). At the end of the season, the team marginally improved, but was still last in the league in OBP (.303) and SLG (.362) and Bagwell announced he would not return as hitting coach. After a five-year gap in contact with the Astros organization, Bagwell accepted a formal invitation from manager A. J. Hinch to be a guest instructor in spring training of 2015. He is currently a special advisor to team owner Jim Crane.
Eric Carlin, a member of the ACMD and former chairman of the English Drug Education Forum, also resigned after the announcement. He said the decision by the Home Secretary was "unduly based on media and political pressure" and there was "little or no discussion about how our recommendation to classify this drug would be likely to impact on young people's behaviour." Some former members of the ACMD and various charity groups expressed concern over the banning of the drug, arguing it would inevitably criminalise users, particularly young people. Others expressed concern that the drug would be left in the hands of black market dealers, who will only compound the problem. Carlin's resignation was specifically linked to the criminalisation of mephedrone; he stated: "We need to review our entire approach to drugs, dumping the idea that legally-sanctioned punishments for drug users should constitute a main part of the armoury in helping to solve our country's drug problems. We need to stop harming people who need help and support". The parliamentary debate was held on 8 April, one day after the 2010 general election had been announced, meaning it was during the so-called "wash-up period" when legislation is passed with little scrutiny. Only one hour was spent debating the ban, and all three parties agreed, meaning no vote was required.
This 1686-amino acid protein belongs to the ADAMTS family and is one of 19 members known in humans. It is a large, multi-domain enzyme that undergoes extensive post-translational modifications, including N- and O-linked glycosylation, chondroitin sulfate attachment, and potential C-mannosylation and O-fucosylation of the thrombospondin (TSP) type 1 domains. The domain structure from the N-terminus to the C-terminus consists of:
Sources: en.wikipedia.org
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。