This is a working overview of 肽纯度, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
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。
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。
=== Prediction of co-evolved protein pairs based on similar phylogenetic trees === It was observed that the phylogenetic trees of ligands and receptors were often more similar than due to random chance. This is likely because they faced similar selection pressures and co-evolved. This method uses the phylogenetic trees of protein pairs to determine if interactions exist. To do this, homologs of the proteins of interest are found (using a sequence search tool such as BLAST) and multiple-sequence alignments are done (with alignment tools such as Clustal) to build distance matrices for each of the proteins of interest. The distance matrices should then be used to build phylogenetic trees. However, comparisons between phylogenetic trees are difficult, and current methods circumvent this by simply comparing distance matrices. The distance matrices of the proteins are used to calculate a correlation coefficient, in which a larger value corresponds to co-evolution. The benefit of comparing distance matrices instead of phylogenetic trees is that the results do not depend on the method of tree building that was used. The downside is that difference matrices are not perfect representations of phylogenetic trees, and inaccuracies may result from using such a shortcut. Another factor worthy of note is that there are background similarities between the phylogenetic trees of any protein, even ones that do not interact. If left unaccounted for, this could lead to a high false-positive rate.
==== Unanimous selection for Most Valuable Player Award (1994) ==== The most productive season in Bagwell's professional career was the strike-shortened 1994 season which set several franchise records. On Opening Day, April 4, against the Montreal Expos, Bagwell hit the game-tying home run while going 3-for-6 as the Astros won in a 12-inning walk-off. For the month of April, he batted .360 with six home runs and added another six home runs in May. In June, he hit 13 home runs, establishing an Astros' franchise record for one month, while batting .394, 11 doubles, .455 OBP, .899 SLG, and 1.354 OPS. On June 24, in a 16–4 rout of the Los Angeles Dodgers at the Astrodome, he hit three home runs, including two in the same inning, becoming the first Astro since Glenn Davis in 1990 to do so. Bagwell was the NL Player of the Week for consecutive weeks on June 19 and June 26 and the NL Player of the Month for June, his second career monthly award. Selected to his first All-Star Game as a reserve, Bagwell had tied Kirby Puckett for the major league RBI lead at 81 going into the All-Star break, and batted .348 with 27 home runs and 74 runs scored. In the All-Star Game, Bagwell entered as a pinch hitter for starting pitcher Greg Maddux, singling off David Cone, and wound up collecting two hits in four at bats. The first player in the majors to reach 100 RBI on July 27, Bagwell homered off José Rijo in a 6–5 win over Cincinnati to give him 101 RBI in his first 101 games. In July, he tied a club record for RBI in any month with 29, which José Cruz and Jimmy Wynn shared.
=== Funding trajectory === Since 1999, the division's funding increased more than six-fold. By 2012, OAM and NCCAM spent a cumulative $1.6 billion in grant funding. Between 1999 and 2009, NCCAM supported approximately 50% of the National Cancer Institute spending on CAM, with the total amount spent on CAM during that time frame $2.856 billion. The NCCIH budget for 2005 was $123 million. For fiscal year 2009 (ending September 30, 2009), it was $122 million. The NIH has also conducted research in alternative medicine at the National Cancer Institute by the Office of Cancer Complementary and Alternative Medicine which, in 2009, had the same $122 million budget as NCCIH. For FY 2009; NIH's total budget was about $29 billion. The NCCIH budget for 2015 was $124.1 million. They requested a $3,459,000 funding increase for their 2016 budget. By FY2023, the NCCIH budget had grown to approximately $170 million annually. The FY2026 President's Budget proposed eliminating NCCIH entirely, but Congress rejected the proposal and maintained NCCIH funding at the FY2025 level.
All ordinary matter is made up of combinations of chemical elements, each with its own atomic number, indicating the number of protons in the atomic nucleus. Additionally, elements may exist in different isotopes, with each isotope of an element differing in the number of neutrons in the nucleus. A particular isotope of a particular element is called a nuclide. Some nuclides are inherently unstable. That is, at some point in time, an atom of such a nuclide will undergo radioactive decay and spontaneously transform into a different nuclide. This transformation may be accomplished in a number of different ways, including alpha decay (emission of alpha particles) and beta decay (electron emission, positron emission, or electron capture). Another possibility is spontaneous fission into two or more nuclides. While the moment in time at which a particular nucleus decays is unpredictable, a collection of atoms of a radioactive nuclide decays exponentially at a rate described by a parameter known as the half-life, usually given in units of years when discussing dating techniques. After one half-life has elapsed, one half of the atoms of the nuclide in question will have decayed into a "daughter" nuclide or decay product. In many cases, the daughter nuclide itself is radioactive, resulting in a decay chain, eventually ending with the formation of a stable (nonradioactive) daughter nuclide; each step in such a chain is characterized by a distinct half-life.
Braden Eric Peters (born 2005 or 2006), better known as Clavicular or Clav, is an American livestreamer, internet personality, and influencer. He rose to popularity on social media in 2025–2026 for promoting "looksmaxxing", a trend of using extreme methods to improve one's appearance, such as "bonesmashing", a pseudoscientific practice involving hitting one's facial bones with a hammer or fist, as well as the use of anabolic steroids and methamphetamine as an appetite suppressant. On September 8, 2026, charges were filed against Peters in Massachusetts state court for criminal rape, drugging, and providing alcohol to a minor.
Sources: en.wikipedia.org
=== Specificity === The specific activities of sv-LAAOs with various L-amino acids have been explored. Many studies show that a number of sv-LAAOs exhibit a preference for hydrophobic L-amino acids as substrates. For example, results have indicated that most sv-LAAOs demonstrate relatively high specificities toward hydrophobic amino acids such as L-Met, L-Leu, and L-Ile in addition to aromatic amino acids such as L-Phe and L-Trp.
resting cellular-membrane potential and the propagation of action potentials in neuronal, muscular, and cardiac tissue. Due to the electrostatic and chemical properties, K+ ions are larger than Na+ ions, and ion channels and pumps in cell membranes can differentiate between the two ions, actively pumping or passively passing one of the two ions while blocking the other. hormone secretion and action vascular tone systemic blood pressure control gastrointestinal motility acid–base homeostasis glucose and insulin metabolism mineralocorticoid action renal concentrating ability fluid and electrolyte balance local cortical monoaminergic norepinephrine, serotonin, and dopamine levels, and through them, sleep/wake balance, and spontaneous activity.
The latter showed yields for LPC extraction from 1% to 7.5% and toxicity screenings confirm that coniferous trees may contain toxins that can be consumed in small amounts, and additional studies including measuring the quantity of each toxin are needed.
== Antidote == In case of a bite from the black mamba, the victim should be treated according to a standard protocol. The most important part of this treatment is the intravenous injection of a polyvalent antivenom. South African Vaccine Producers produces this antivenom. Polyvalent means that it can be used for different snakebites: vipers, mambas and cobras. Large quantities of the antivenom must be injected to counter the effects of the venom. The polyvalent antivenin is produced by injecting horses with adapted venom. The venom is first detoxified to prevent too much damage and death. This is mostly done by complexing the venom with an aldehyde like formalin. The venom is also administered with an adjuvant, like aluminium hydroxide or sodium alginate, to stimulate the immunological response. When the venom is injected, the body will produce antibodies. These will bind components – the variability of peptides – of the venom, which prevent further activity of the molecule and are ultimately removed by the immune system of the body. These antibodies are collected and purified from the blood and then packaged in mostly a liquid form. Horses are used because of the large blood volume. The final antivenom product expires after 5 years and needs to preferentially be kept cool, 4-8 °C. It can, however, survive different environmental situations for some weeks to months, without losing its potency. Because several venoms of different snakes are injected over time, the horse will develop different antibodies against all the venoms.
Sources: en.wikipedia.org
Typically found in young children and is the most common cause at this age. Generally occurs after a viral infection of adenovirus (types 3, 7, and 21), measles (rubeola), mycoplasma, CMV, influenza, and parainfluenza. Swyer-James syndrome is a rare complication of bronchiolitis obliterans caused by measles or adenovirus. Post-infectious bronchiolitis obliterans is most common in the southern hemisphere particularly in countries such as Brazil, Argentina, Australia, Chile and New Zealand. There was a large prevalence of the disease in these areas during the 1990s and early 2000s. In one hospital in Buenos Aires, the Ricardo Gutiérrez Children's hospital, the disease accounted for 14% of their inpatient respiratory population from 1993 to 2002. As such, much of the information about post-infectious bronchiolitis obliterans has come from research out of South America. The most significant risk factors for the disease are infection with adenovirus and the need for ventilator support. In contrast with another cause of bronchiolitis obliterans in children, Steven's Johnson's syndrome, post-infectious bronchiolitis obliterans tends to be a chronic but non-progressive disease. The disease can have varying impact on children and their quality of life, which has been studied by lung function tests, as well as their exercise tolerance. Children with lower lung function based on their pulmonary function testing, have lower exercise tolerance, which compounds the impact of the disease on cardiovascular function as they are not able to maintain age appropriate aerobic fitness.
Other experiments show that a single miRNA may repress the production of hundreds of proteins, but that this repression often is relatively mild (less than 2-fold). The effects of miRNA dysregulation of gene expression seem to be important in cancer. For instance, in gastrointestinal cancers, nine miRNAs have been identified as epigenetically altered and effective in down regulating DNA repair enzymes. The effects of miRNA dysregulation of gene expression also seem to be important in neuropsychiatric disorders, such as schizophrenia, bipolar disorder, major depression, Parkinson's disease, Alzheimer's disease and autism spectrum disorders.
By choosing porous graphitic carbon as a stationary phase for liquid chromatography, even non derivatized glycans can be analyzed. Detection is here done by mass spectrometry, but in instead of MALDI-MS, electrospray ionisation (ESI) is more frequently used.
== Classification == Argiotoxin can be classified, according to the 1980s classification of spider venoms, as a toxin of the acylpolyamines family, which contains more than 100 different chemical structures of closely related toxins. Acylpolyamines are neurotoxic compounds that are found only in the venom glands of spiders at a picomolar level. Argiotoxins are classified into three different categories according to its chromophore's nature: the argiopine type, the argiopinine type and the pseudoargiopinine type.
. In conventional chromatography, separation of similar compounds can be improved by gradient elution. In MEKC, however, techniques must be used to extend the elution range to separate strongly retained analytes. Elution ranges can be extended by several techniques including the use of organic modifiers, cyclodextrins, and mixed micelle systems. Short-chain alcohols or acetonitrile can be used as organic modifiers that decrease
Sources: en.wikipedia.org
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.