If you have been reading about 甲硫氨酸氧化 and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-10-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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。
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.
| Property | Value | Notes |
|---|---|---|
| 分子式 | C37H51N9O10S | 游离碱形式 |
| 等电点 | 约 6.5 | 估算值，随缓冲体系变化 |
| 主要降解途径 | 水解与氧化 | 侧链氧化最为常见 |
| 溶液储存 | 2 至 8 摄氏度避光 | 避免反复冻融 |
| 常规分析手段 | 反相色谱与质谱联用 | 氨基酸分析辅助核对 |
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。
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。
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.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
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.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
== Structure–activity relationship == Even though μ-opioid receptor (MOR) targeting drugs have been used for a long time, not much is known about the structure-activity relationship and the ligand-receptor interactions on the basis of well-defined biological effects on receptor activation or inhibition. Also, the distinction in the receptor-ligand interaction patterns of agonists and antagonists is not known for sure. One theory states that the morphinans biological activity could be determined by the size of the N-substituents. For example, antagonists usually have larger substituents, such as allyl- or cyclopropyl methyl at the morphinan nitrogen, while agonists generally contain a methyl group. On the other hand, agonist activity is also shown in ligands with larger groups at the morphinan nitrogen, and therefore this hypothesis is challenged.
=== Working conditions === Documentary translators very often have to meet tight deadlines. Normally, the translator has between five and seven days to hand over the translation of a 90-minute programme. Dubbing studios typically give translators a week to translate a documentary, but in order to earn a good salary, translators have to deliver their translations in a much shorter period, usually when the studio decides to deliver the final programme to the client sooner or when the broadcasting channel sets a tight deadline, e.g. on documentaries discussing the latest news. Another problem is the lack of a post-production script or the poor quality of the transcription. A correct transcription is essential for a translator to do their work properly; however, many times the script is not even given to the translator, which is a major impediment since documentaries are characterised by "the abundance of terminological units and very specific proper names". When the script is given to the translator, it is usually poorly transcribed or outright incorrect making the translation unnecessarily difficult and demanding because all of the proper names and specific terminology have to be correct in a documentary programme in order for it to be a reliable source of information, hence the translator has to check every term on their own. Such mistakes in proper names are for instance: "Jungle Reinhard instead of Django Reinhart, Jorn Asten instead of Jane Austen, and Magnus Axle instead of Aldous Huxley".
In the US, almost exclusively corn (more precisely, corn syrup) is used as glucose source for the production of isoglucose, which is a mixture of glucose and fructose, since fructose has a higher sweetening power – with same physiological calorific value of 374 kilocalories per 100 g. The annual world production of isoglucose is 8 million tonnes (as of 2011). When made from corn syrup, the final product is high-fructose corn syrup (HFCS).
The hypothalamus has a central neuroendocrine function, most notably by its control of the anterior pituitary, which in turn regulates various endocrine glands and organs. Releasing hormones (also called releasing factors) are produced in hypothalamic nuclei then transported along axons to either the median eminence or the posterior pituitary, where they are stored and released as needed.
Sources: en.wikipedia.org
"A quick and simple introduction to Drosophila melanogaster". Drosophila Virtual Library. "Drosophila Genomics Resource Center" – collects, maintains and distributes Drosophila DNA clones and cell lines. "Bloomington Drosophila Stock Center" – collects, maintains and distributes Drosophila melanogaster strains for research "FlyBase—A Database of Drosophila Genes & Genomes". Archived from the original on November 3, 2018. Retrieved January 28, 2011. "NCBI Map Viewer – Drosophila melanogaster". Archived from the original on June 5, 2003. "Drosophila Virtual Library". "The Berkeley Drosophila Genome Project". "FlyMove". – video resources for Drosophila development "Drosophila Nomenclature—naming of genes". Archived from the original on October 8, 2011. View the Fruitfly genome on Ensembl View the dm6 genome assembly in the UCSC Genome Browser Manchester Fly Facility – for the public Archived 2015-05-13 at the Wayback Machine from the University of Manchester The droso4schools website with school-relevant resources about Drosophila Part 1 of the "Small fly: BIG impact" educational videos explaining the history and importance of the model organism Drosophila. Part 2 of the "Small fly: BIG impact" educational videos explaining how research is carried out in Drosophila. "Inside the Fly Lab"—broadcast by WGBH and PBS, in the program series Curious, January 2008. "How a Fly Detects Poison" Deprecated link archived 2013-01-13 at archive.today—WhyFiles.org article describes how the fruit fly tastes a larva-killing chemical in food.
== Vendors == To list on a market, a vendor may have undergone an application process via referral, proof of reputation from another market or given a cash deposit to the market. Many vendors list their wares on multiple markets, ensuring they retain their reputation even should a single market place close. Grams (closed December 2017) had launched "InfoDesk" to allow central content and identity management for vendors as well as PGP key distribution. Meanwhile, individual law enforcement operations regularly investigate and arrest individual vendors and those purchasing significant quantities for personal use. A February 2016 report suggested that a quarter of all DNM purchases were for resale.
== Bibliography == Catinon, M., Ayrault, S., Boudouma, O., Bordier, L., Agnello, G., Reynaud, S., & Tissut, M. (2014). Isolation of technogenic magnetic particles. Science of the Total Environment, 475, 39-47 (abstract).
Sources: en.wikipedia.org
== Hosts == D. dadantii causes disease on several different ornamental and horticultural host plants throughout the world including: tropical, subtropical, and temperate climates. The host range of D. dadantii continues growing as new susceptible species are continuously being documented. It has also been found in soils, rivers and irrigation water. Host specificity is not yet fully understood. Originally pathovar groups were documented according to the hosts from which they were isolated. Today 50+ species have been identified and more are possible if another classification system based on biovars were to be used. Disease is most often reported on bananas, carnations, and chrysanthemums, but the list of host species is quite vast. Important host families and species economically affected include:
=== Eligibility of minors === While the WPATH standards of care generally require the patient to have reached the age of medical majority, they include a separate section devoted to children and adolescents. Prepubescent children do not have access to medical intervention for gender-affirming therapy. After puberty, some medical intervention is available for adolescents depending on specific criteria for gender incongruence diagnosis, capacity for informed consent, and mental and physical health. According to a study by JAMA Pediatrics published in January 2025, less than 0.1% of adolescents covered by private medical insurance in the US take gender-affirming medication to treat gender dysphoria.
=== Brazil === Between 2005 and 2021, Brazil had 1,576 suspected cases of CJD, of which 547 were confirmed. In August 2026, Brazilian aviation expert Lito Sousa was diagnosed with CJD. He died two months later, on October 1.
Sources: en.wikipedia.org
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。
甲硫氨酸侧链含硫醚，在氧气、光照或金属离子存在时容易被氧化。氧化产物极性略增，常在色谱图上表现为主峰之前的肩峰或前伸峰。
通常建议冷藏避光，并在较短时间内使用。不存在适用于所有配方的统一期限，具体取决于浓度、缓冲体系与容器材质。
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.