A practical reference on ACTH(4–10): what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-03-22. Anything still debated is marked as such rather than presented as settled.
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。
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.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
| Property | Value | Notes |
|---|---|---|
| 外观 | 白色至类白色粉末 | 常见于冻干制剂 |
| 溶解度 | 易溶于水 | 在极性溶剂中一般也可溶 |
| 建议储存温度 | -20 °C | 冻干粉，避光密封 |
| 常见分析手段 | 反相高效液相色谱 | 常与质谱联用 |
| 主要降解路径 | 水解与氧化 | 溶液状态更显著 |
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.
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.
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.
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.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
=== As a set === Conceptually a mole is similar to words like "pair" or "dozen". These words describe a set of identical objects—i.e. a collection or aggregate of the objects themselves, not the numbers 2 or 12. The unusual and daunting aspect of a mole is that the number of objects in the set, given by the Avogadro number, is difficult to comprehend. To be useful as a unit, the mole needs to describe the amount in a sample containing a number of atoms (or other elementary entities) that can be manipulated in an ordinary chemistry lab. Atoms are so small that not just trillions but trillions-of-trillions of atoms are needed to create an aggregate large enough to work with.
=== Pharmacodynamics === Carisoprodol's structural similarity to meprobamate indicates GABAergic activity, including GABAA agonism, similar to the mechanism of benzodiazepines but distinct (benzodiazepines are positive allosteric modulators of the GABA A receptor, and have no direct agonist activity but rather increase the potency of the endogenous agonist GABA at this receptor). Carisoprodol thus not only works as a muscle relaxant but also helps with anxiety. Unlike benzodiazepines, carisoprodol does not treat or prevent seizures. In fact, it increases the risk of seizures, with the risk being even higher when discontinuing the drug after long-term use, especially if it is stopped suddenly, precipitating withdrawal.
plantarum uses extracellular electron transfer to increase the NAD+/NADH ratio, accelerate fermentation, generate more ATP through the substrate-level phosphorylation, and accumulate more biomass. Lactiplantibacillus plantarum, like many lactobacilli, can be cultured using MRS media.
where the carbon-12 nucleus used in the first reaction is regenerated in the last reaction. After the two positrons (emitted by beta-plus decay) annihilate with two ambient electrons producing an additional 2.04 MeV, the total energy released in one cycle is 26.73 MeV; in some texts, authors are erroneously including the positron annihilation energy in with the Q-value for beta-decay and then neglecting the equal amount of energy released by annihilation, leading to possible confusion. All values are calculated with reference to the Atomic Mass Evaluation 2003. The limiting (slowest) reaction in the CNO-I cycle is the proton capture on 147N. In 2006 it was experimentally measured down to stellar energies, revising the calculated age of globular clusters by around 1 billion years. The neutrinos emitted in beta decay will have a spectrum of energy ranges, because although momentum is conserved, the momentum can be shared in any way between the positron and neutrino, with either emitted at rest and the other taking away the full energy, or anything in between, so long as all the energy from the Q-value is used. The total momentum received by the positron and the neutrino is not great enough to cause a significant recoil of the much heavier daughter nucleus and hence, its contribution to kinetic energy of the products, for the precision of values given here, can be neglected. Thus the neutrino emitted during the decay of nitrogen-13 can have an energy from zero up to 1.20 MeV, and the neutrino emitted during the decay of oxygen-15 can have an energy from zero up to 1.73 MeV.
Sources: en.wikipedia.org
As late as the 1960s, the element was also referred to simply as emanation. The first synthesized compound of radon, radon fluoride, was obtained in 1962. Even today, the word radon may refer to either the element or its isotope 222Rn, with thoron remaining in use as a short name for 220Rn to stem this ambiguity. The name actinon for 219Rn is rarely encountered today, probably due to the short half-life of that isotope. The danger of high exposure to radon in mines, where exposures can reach 1,000,000 Bq/m3, has long been known. In 1530, Paracelsus described a wasting disease of miners, the mala metallorum, and Georg Agricola recommended ventilation in mines to avoid this mountain sickness (Bergsucht). In 1879, this condition was identified as lung cancer by Harting and Hesse in their investigation of miners from Schneeberg, Germany. The first major studies with radon and health occurred in the context of uranium mining in the Joachimsthal region of Bohemia. In the US, studies and mitigation only followed decades of health effects on uranium miners of the Southwestern US employed during the early Cold War; standards were not implemented until 1971. In the early 20th century in the US, gold contaminated with the radon daughter 210Pb entered the precious metal supply chain of that country's jewelry industry. Gold brachytherapy seeds that had held 222Rn were illicitly or unknowingly sold and melted down. The presence of radon in indoor air was documented as early as 1950.
== Other uses == Seed Science and Technology, a journal about seed science published by the International Seed Testing Association SST (typeface) Swiss Solvency Test, a framework for the regulation of the insurance industry in Switzerland Serious Sam: Tormental, a video game by Gungrounds Sales and Services Tax, a type of tax in Malaysia
Bully: Andy Height: 6'2 Weight: 199 lbs Victim(s): Steven and Taylor Fighter: Jason "Mayhem" Miller Height: 6'1 Weight: 198 lbs Money earned by Bully: $0 Money earned by victim(s): $10,000 Original airing:
Sources: en.wikipedia.org
Typical amino acids - there are several other amino acids which they can change into through single nucleotide substitution. Typical amino acids and their alternatives usually have similar physicochemical properties. Leucine is an example of a typical amino acid. Idiosyncratic amino acids - there are few similar amino acids that they can mutate to through single nucleotide substitution. In this case most amino acid replacements will be disruptive for protein function. Tryptophan is an example of an idiosyncratic amino acid.
On 29 January, Iraqi forces attacked and occupied the lightly defended Saudi city of Khafji with tanks and infantry. The Battle of Khafji ended two days later when the Iraqis were driven back by the Saudi Arabian National Guard, supported by Qatari forces and US Marines. The allied forces used extensive artillery fire. Both sides suffered casualties, although Iraqi forces sustained substantially more dead and captured than the allied forces. Eleven Americans were killed in two separate friendly fire incidents, an additional 14 US airmen were killed when their AC-130 gunship was shot down by an Iraqi surface-to-air missile, and two US soldiers were captured during the battle. Saudi and Qatari forces had a total of 18 dead. Iraqi forces in Khafji had 60–300 dead and 400 captured. The Battle of Khafji was an example of how air power could single-handedly hinder the advance of enemy ground forces. Upon learning of Iraqi troop movements, 140 coalition aircraft were diverted to attack an advancing column consisting of two armored divisions in battalion-sized units. Precision stand-off attacks were conducted during the night and through to the next day. Iraqi vehicle losses included 357 tanks, 147 armored personnel carriers, and 89 mobile artillery pieces. Some crews simply abandoned their vehicles upon realizing that they could be destroyed by guided bombs, stopping the divisions from massing for an organized attack on the town.
== Biography == Madeleine-Angelique was born in Paris on 22 November 1684 to the actor Paul Poisson. Madeleine-Angélique married a Spanish nobleman, Don Gabriel de Gomez, thinking he was rich. When she discovered her husband was burdened with debt, she turned to writing as a hope to escape poverty. Her first a tragedy, Habis, was released in 1714 to much critical appeal, being played at the Comédie-Française with a revival in 1732. Between 1722 and 1772, Gomez published eight editions of Les Journées amusantes, with the work being translated into English by Eliza Haywood. While most of her work was published under the name Madame de Gomez (Mme de Gomez), some of her works have been published under the pseudonym M.P.V.D.G. She died in Saint-Germain-en-Laye on 28 December 1770 at the age of 86.
== Definition of statistical coupling energy == Statistical coupling energy measures how a perturbation of amino acid distribution at one site in an MSA affects the amino acid distribution at another site. For example, consider a multiple sequence alignment with sites (or columns) a through z, where each site has some distribution of amino acids. At position i, 60% of the sequences have a valine and the remaining 40% of sequences have a leucine, at position j the distribution is 40% isoleucine, 40% histidine and 20% methionine, k has an average distribution (the 20 amino acids are present at roughly the same frequencies seen in all proteins), and l has 80% histidine, 20% valine. Since positions i, j and l have an amino acid distribution different from the mean distribution observed in all proteins, they are said to have some degree of conservation. In statistical coupling analysis, the conservation (ΔGstat) at each site (i) is defined as:
Sources: en.wikipedia.org
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。
公开资料对此没有统一答案。普遍建议现配现用，或冷藏并在数日内用完。含甲硫氨酸的序列更易氧化，放置时间越长风险越高。
反相高效液相色谱是最常用的手段，配合质谱确认分子量。氨基酸组成分析和肽图分析可补充序列层面的验证。
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.