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 2026-07-27 and is reviewed periodically as new material appears.
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
| Property | Value | Notes |
|---|---|---|
| 化学类别 | 合成七肽 | ACTH(4-10) 结构类似物 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | 单字母写作 MEHFPGP |
| 分子量 | 约 813.9 Da | 随确切形式和盐型略有变化 |
| 常见同义词 | ACTH(4-10) 类似物 | 俄语文献称 Семакс |
| 开发来源 | 俄罗斯 | 二十世纪八十年代 |
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.
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.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
The Dutch sprinter Foekje Dillema was expelled from the 1950 national team after she refused a mandatory sex test in July 1950; later investigations revealed a Y-chromosome in her body cells, and the analysis showed that she was probably a 46,XX/46,XY mosaic female. In 1953, a human chimera was reported in the British Medical Journal. A woman was found to have blood containing two different blood types. Apparently this resulted from her twin brother's cells living in her body. A 1996 study found that such blood group chimerism is not rare. In 2002, an article in the New England Journal of Medicine described a woman, later identified as Karen Keegan, in whom tetragametic chimerism was unexpectedly identified after she underwent preparations for kidney transplant. Those preparations for the transplant required the patient and her immediate family to undergo histocompatibility testing, the result of which had suggested that she was not the biological mother of two of her three children. In 2002, Lydia Fairchild was denied public assistance in Washington state when DNA evidence appeared to show that she was not the mother of her children. A lawyer for the prosecution heard of the case of Karen Keegan in New England, and suggested the possibility to the defense, who were able to show that Fairchild, too, was a chimera with two sets of DNA, and that one of those sets could have produced the children. In 2009, singer Taylor Muhl's large torso birthmark was diagnosed as resulting from chimerism.
=== Interpretation of results === Laboratory results may differ depending on the analytical technique, the age of the subject, and biological variation among individuals. Higher levels of HbA1c are found in people with persistently elevated blood sugar, as in diabetes mellitus. While diabetic patients' treatment goals vary, many include a target range of HbA1c values. A diabetic person with good glucose control has an HbA1c level that is close to or within the reference range. The International Diabetes Federation and the American College of Endocrinology recommend HbA1c values below 48 mmol/mol (6.5 DCCT %), while the American Diabetes Association recommends HbA1c be below 53 mmol/mol (7.0 DCCT %) for most patients. Results from large trials in 2008–09 suggested that a target below 53 mmol/mol (7.0 DCCT %) for older adults with type 2 diabetes may be excessive: Below 53 mmol/mol, the health benefits of reduced A1c become smaller, and the intensive glycemic control required to reach this level leads to an increased rate of dangerous hypoglycemic episodes. A retrospective study of 47,970 type 2 diabetes patients, aged 50 years and older, found that patients with an HbA1c more than 48 mmol/mol (6.5 DCCT %) had an increased mortality rate, but a later international study contradicted these findings.
Terpenes and terpenoids of many kinds are found in resinous plants such as the conifers. They are aromatic and serve to repel herbivores. Their scent makes them useful in essential oils, whether for perfumes such as rose and lavender, or for aromatherapy. Some have had medicinal uses: thymol is an antiseptic and was once used as a vermifuge (anti-worm medicine).
Sources: en.wikipedia.org
== Astronomy and spaceflight == There is no scientific evidence that the motion of stars, planets, and other celestial bodies influences the fates of humans, and astrology has repeatedly been shown to have no explanatory power in predicting future events. Astronauts in orbit have the sensation of being weightless because they are in free fall around the Earth, not because they are so far away from the Earth that its gravitational pull is negligible. For example, on the International Space Station the Earth's gravity is nearly 90% as strong as at the surface. Objects orbiting in space would not remain in orbit if not for the gravitational force, and gravitational fields extend infinitely, though the strength of the gravitational force is attenuated with distance. There is no limit to the distance across which two objects exert gravitational forces upon one another. The dark side of the Moon receives about the same amount of light from the Sun as the near side. Since the same side of the Moon always faces the Earth due to tidal locking, the far side had not been seen until Luna 3 photographed it in 1959. Hence, "dark" refers to the far side being unseen from Earth, not to any lack of illumination by the Sun. Black holes have the same gravitational effects as any other equal mass in their place. They will draw objects towards them according to distance and mass, just as any other celestial body does, except at very close distances to the black hole, comparable to its Schwarzschild radius.
There are recipes for pork stews and fish stews in the Roman cookery book Apicius, believed to date from the 4th century AD. Le Viandier, one of the oldest cookbooks in French, written in the early 14th century by the French chef known as Taillevent, has ragouts or stews of various types in it.
Cycloprop-2-ene carboxylic acid is a mycotoxin found in some mushrooms such as Russula subnigricans. When ingested, the molecule is known to cause dose-dependent rhabdomyolysis. In mice, the oral LD50 of this molecule is 2.5 mg/kg and poisoning is indicated by an increase in blood creatine phosphokinase levels. Polymerization via the ene reaction abolishes toxicity. 3-(Cycloprop-2-en-1-oyl)oxazolidinones are a class of ‘unusually stable’ derivatives of the mycotoxin that have been synthesized by Fox et al. As mentioned by Fox et al, this class of ‘unusually stable’ derivatives are dienophiles when involved in a Diels-Alder reaction. The pure substance is a hydroscopic white solid that is able to decarboxylate exothermically.
Sources: en.wikipedia.org
C3Cl4 + AlCl3 → [C3Cl3]+AlCl−4 Tetrachlorocyclopropene can be converted to tris(tert-butyldimethylsilyl)cyclopropene. Hydride abstraction with nitrosonium tetrafluoroborate yields the trisilyl-substituted cyclopropenium cation.
Antithrombin I (AT I) refers to the binding of thrombin to fibrin, after thrombin has activated fibrinogen, at a non-catalytic binding site of thrombin. Antithrombin II (AT II) refers to a cofactor in plasma, which together with heparin interferes with the interaction of thrombin and fibrinogen. Antithrombin III (AT III) refers to a substance in plasma that inactivates thrombin. Antithrombin IV (AT IV) refers to an antithrombin that becomes activated during and shortly after blood coagulation. Only AT III and possibly AT I are medically significant. AT III is generally referred to solely as "antithrombin" and it is antithrombin III that is discussed in this article. Antithrombin has a half-life in blood plasma of around 3 days. The normal antithrombin concentration in human blood plasma is high at approximately 0.12 mg/ml, which is equivalent to a molar concentration of 2.3 μM. Antithrombin has been isolated from the plasma of a large number of species additional to humans. As deduced from protein and cDNA sequencing, cow, sheep, rabbit and mouse antithrombins are all 433 amino acids in length, which is one amino acid longer than human antithrombin. The extra amino acid is thought to occur at amino acid position 6. Cow, sheep, rabbit, mouse, and human antithrombins share between 84 and 89% amino acid sequence identity. Six of the amino acids form three intramolecular disulfide bonds, Cys8-Cys128, Cys21-Cys95, and Cys248-Cys430. They all have four potential N-glycosylation sites.
== Release == Stargirl premiered on DC Universe on May 18, 2020, with the first season consisting of 13 episodes. The series was originally intended to premiere on May 11, seven days before its official release. The series was released in 4K Ultra HD on DC Universe. In November 2019, The CW announced to broadcast each episode the day after it premieres on the streaming service, with each episode available to stream on The CW's online platforms after its broadcast. Stargirl started airing on The CW on May 19, 2020, at 8 pm. Some episodes have content removed when they air on The CW to allow for the network's commercials, notably approximately eight minutes in each of the first two episodes. DC Universe streamed the full episodes, and Johns said starting with the third episode, both releases are "almost identical". The series release plans shifted and it stayed in post-production longer to accommodate the broadcast on The CW to accomplish the adjustments that had to be made. Scenes removed in the first episode from The CW broadcast included: establishing shots of Barbara Whitmore's new job, and Pat's auto shop; an interaction between Courtney and Cindy Burman in the halls of Blue Valley High School that Alex Zalben of Decider said was "clear set-up for later" but helped strengthen Courtney's emotional arc; and Mark Ashworth's scenes as "a mysterious, extremely creepy bearded janitor", which Zalben said was more of "a fun Easter egg that will pay dividends down the road"; and Courtney finding a newspaper article about Starman and Stripesy.
== Trademark dispute and grocery brand == In 2002, Boston Pizza commenced a lawsuit against Boston Market in the Federal Court of Canada over the trademark use of the word "Boston" in Canada. In its defense, Boston Market alleged that Boston Pizza's trademarks were invalid because it described a style of pizza from a specific area. The dispute continued after Boston Market ceased operations in Canada in 2004. The parties settled the dispute in 2008 under an agreement that Boston Market would not use the words "Boston" or "Boston Market" in Canada for five years for restaurants or any food or drink products (other than pre-packaged food products, but not including pizza and lasagna). Boston Market also agreed that it would not challenge Boston Pizza's use in Canada of any trademark that uses the words "Boston" or "Boston Pizza" (with certain exceptions).
Sources: en.wikipedia.org
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。
Semax 被描述为 ACTH(4-10) 的结构类似物，两者共享部分序列特征。它保留了该片段的部分神经相关活性方向，但去除了完整片段带来的激素释放效应。二者并非同一物质，也不能互相替代。
加入的 Pro-Gly-Pro 三肽被普遍认为能提升分子对蛋白水解酶的稳定性。这种设计让短肽在体内维持时间更长。具体延长的程度以及不同组织中是否一致，文献中仍存在不同报告。
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.