reversed-phase HPLC 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 2025-09-01 and is reviewed periodically as new material appears.
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。
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.
| 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。
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.
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.
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.
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.
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.
== Commonly monitored vaccines == The vaccine vial monitor is intended for use on vaccines which may travel outside of the cold chain, but its use on certain vaccines has had an especially notable impact.
== Portrayals in news == Inaccurate portrayals of mental health in the news ultimately affect the audience's thoughts, attitudes, opinions, and beliefs, not only for the mentally ill but also for the illnesses themselves, the treatment required, and the public policy necessary to implement initiatives for change. However, these dramatic stories may not be the only culprit for swaying public opinion. Consistent patterns of misinformation, framing, and one-sided perspectives have the same ability to shape public perception. In 1991, a content analysis of United Press International stories found that stories about psychiatric patients usually involved violent crimes. In a similar study by Wahl, Wood, and Richards, they analyzed the common themes present in 1999 stories about mental illness amongst six major newspapers: The New York Times, The Washington Post, St. Louis Post-Dispatch, The Boston Globe, Los Angeles Times, and the St. Petersburg Times (Tampa Bay Times). Of the 300 randomly selected stories containing the phrase "mental illness," dangerousness was the overwhelming theme across all six publications, with 26% involving violence or criminal activity by a mentally ill person. The consistent pattern of linking mental illness and violence not only leads to the public being fearful or avoidant of mentally ill people but also less likely to offer or support community care.
=== Thymus === The thymus gland is one of the first organs to degenerate in normal healthy individuals. Researchers from the University of Edinburgh have succeeded in regenerating a living organ that closely resembles a juvenile thymus in terms of structure and gene expression profile.
=== Events === Japan Tamagokake Gohan Symposium: Held annually in Unnan, Shimane since 2005, originating from the development of the local TKG soy sauce "Otamahan." The symposium discusses the history and appeal of TKG and led to October 30th being designated "Tamagokake Gohan Day." Aspam Tamagokake Gohan Fair: Held in Aomori, Aomori in 2009 at the Aomori Prefecture Tourist Center Aspam. Guinness World Record - Town Revitalization Nippon: In Pippu, Hokkaido, on August 4, 2024, a Guinness World Record was set for the "most people making tamago kake gohan simultaneously." Proposed by local junior high students to promote the town's products (Yumepirika rice, "Kappa no Kenran" eggs, Pippu green onion soy sauce), 325 participants successfully made TKG within 5 minutes.
Sources: en.wikipedia.org
The amino acid side-chain of arginine consists of a 3-carbon aliphatic straight chain, the distal end of which is capped by a guanidinium group, which has a pKa of 13.8, and is therefore always protonated and positively charged at physiological pH. Because of the conjugation between the double bond and the nitrogen lone pairs, the positive charge is delocalized, enabling the formation of multiple hydrogen bonds.
== Metabolism == Most members of the genus Haemophilus require at least one of these blood factors for growth: hemin (sometimes called 'X-factor') and/or nicotinamide adenine dinucleotide (NAD; sometimes called 'V-factor'); they usually will not grow on blood agar plates. While NAD is released into blood agar by red blood cells, hemin is bound to the blood cells and is unavailable to bacteria in this medium which prevents the growth of many Haemophilus species. They are unable to synthesize important parts of the cytochrome system needed for respiration, and they obtain these substances from the heme fraction of blood hemoglobin. Clinical laboratories use tests for the hemin and NAD requirement to identify the isolates as Haemophilus species. The species Haemophilus haemoglobinophilus is an exception to this, as it has been shown to grow well on both blood and chocolate agars. Chocolate agar is an excellent Haemophilus growth medium, as it allows for increased accessibility to these factors. Alternatively, Haemophilus is sometimes cultured using the "Staph streak" technique: both Staphylococcus and Haemophilus organisms are cultured together on a single blood agar plate. In this case, Haemophilus colonies will frequently grow in small "satellite" colonies around the larger Staphylococcus colonies because the metabolism of Staphylococcus produces the necessary blood factor byproducts required for Haemophilus growth.
The Social Democrats won the election with a minority government and could not gather a strong enough mandate for the incorporation of South Schleswig. This outcome created outrage within the Danish population and was considered a scandal. Due to the forced migrations of Germans between 1944 and 1950, Schleswig-Holstein took in almost a million refugees after the war, increasing its population by 33%. A pro-Danish political movement arose in Schleswig, with transfer of the area to Denmark as an ultimate goal. This was supported neither by the British occupation administration nor the Danish government. In 1955, the German and Danish governments issued the Bonn-Copenhagen Declarations confirming the rights of the ethnic minorities on both sides of the border. Conditions between the nationalities have since been stable and generally respectful.
Sources: en.wikipedia.org
In 1998, the entire Festina team were excluded from the Tour de France following the discovery of a team car containing large amounts of various performance-enhancing drugs. The team director later admitted that some of the cyclists were routinely given banned substances. Six other teams pulled out in protest including Dutch team TVM who left the tour still being questioned by the police. The Festina scandal overshadowed cyclist Marco Pantani's tour win, but he himself later failed a test. The infamous "Pot Belge" or "Belgian mix" has a decades-long history in pro cycling, among both riders and support staff. David Millar, the 2003 World-Time Trial Champion, admitted using EPO, and was stripped of his title and suspended for two years. Roberto Heras was stripped of his victory in the 2005 Vuelta a España and suspended for two years after testing positive for EPO.
In Truth Social, Trump also claimed that Xi agreed on rebranding artificial intelligence to "super intelligence", saying "Like almost everyone else, he seemed to like calling the poorly and inaccurately named Artificial Intelligence to a far more accurate and important name, SUPER INTELLIGENCE" and that "That would be ‘SUPER!’ Everyone last night agreed, also." In response, the spokesperson of the Ministry of Foreign Affairs of China said that China respects the US's use of the term "super intelligence". Russian President Vladimir Putin commented on the visit, saying that Russia welcomes dialogue between the United States and China, and that whatever results the United States and China achieve will affect the entire world economy. After Xi left the US, President Trump called Japanese Prime Minister Sanae Takaichi. Trump explained to Takaichi the content of his talks with Xi Jinping during the meeting. The two exchanged views on China-related issues. Takaichi said that she and Trump maintained communication before and after Xi's visit, showing the close relationship between the US and Japan.
Radiation burns may be caused by protracted exposure to ultraviolet light (such as from the sun, tanning booths or arc welding) or from ionizing radiation (such as from radiation therapy, X-rays or radioactive fallout). Sun exposure is the most common cause of radiation burns and the most common cause of superficial burns overall. There is significant variation in how easily people sunburn based on their skin type. Skin effects from ionizing radiation depend on the amount of exposure to the area, with hair loss seen after 3 Gy, redness seen after 10 Gy, wet skin peeling after 20 Gy, and necrosis after 30 Gy. Redness, if it occurs, may not appear until some time after exposure. Radiation burns are treated the same as other burns. Microwave burns occur via thermal heating caused by the microwaves. While exposures as short as two seconds may cause injury, overall this is an uncommon occurrence.
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.