Everything below concerns synthetic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-20. Numbers and descriptions here follow the published literature rather than marketing material.
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。
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| 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 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.
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.
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.
== Development and production == Pimecrolimus was developed by Novartis. Its development number was ascomycin derivative ASM 981. The New Drug Application (NDA) was filed December 15, 2000. It received US FDA approval on December 13, 2001. At its US approval, it was one of the first new eczema treatments introduced since the topical corticosteroids of the 1950s. It is available as a topical cream, once marketed by Novartis. Since early 2007, Galderma has been promoting the compound in Canada. The trade name is Elidel.
=== Battle of Britain === During the battle, Chain Home stations – most notably the one at Ventnor, Isle of Wight – were attacked several times between 12 and 18 August 1940. On one occasion a section of the radar chain in Kent, including the Dover CH, was put out of action by a lucky hit on the power grid. Though the wooden huts housing the radar equipment were damaged, the towers survived owing to their open steel girder construction. Because the towers survived intact and the signals were soon restored, the Luftwaffe concluded the stations were too difficult to damage by bombing and left them alone for the remainder of the war.
=== Personal life and death === Dyson married his first wife, the Swiss mathematician Verena Huber, on 11 August 1950. They had two children, Esther and George, before divorcing in 1958. In November 1958 he married Imme Jung, with whom he had four daughters. Dyson died on 28 February 2020 at Penn Medicine Princeton Medical Center in Plainsboro Township, New Jersey, from complications following a fall. He was 96.
Sources: en.wikipedia.org
== Nomenclature == Hemolysis is sometimes called hematolysis, erythrolysis, or erythrocytolysis. The words hemolysis () and hematolysis () both use combining forms conveying the idea of "lysis of blood" (hemo- or hemato- + -lysis). The words erythrolysis () and erythrocytolysis () both use combining forms conveying the idea of "lysis of erythrocytes" (erythro- ± cyto- + -lysis). Red blood cells (erythrocytes) have a short lifespan (approximately 120 days), and old (senescent) cells are constantly removed and replaced with new ones via erythropoiesis. This breakdown/replacement process is called erythrocyte turnover. In this sense, erythrolysis or hemolysis is a normal process that happens continually. However, these terms are usually used to indicate that the lysis is pathological.
Lücking and colleagues (2021) emphasize distinguishing real species from minor variants with differing allele frequencies or subtle sequence divergence. These issues reflect the balance between scientific progress and maintaining a practical, stable nomenclature for ecological and conservation work. The LPR framework is one attempt to impose a higher bar: requiring evidence of reproductive isolation or ecological differentiation, not just genetic distinctness, to call something a new species. Additionally, nomenclatural stability is an ongoing issue. When molecular studies reorder relationships, it often necessitates changes in genus or family assignments. The 2016 global lichen classification (and its 2017 update) made hundreds of such changes to align names with phylogeny. They noted that fully half of all lichen genera had to be moved to a different family or order compared to the previous decade's understanding. These scientifically justified changes can be disruptive for end-users like ecologists or land managers who suddenly have to learn new names for familiar organisms. The challenge for systematists is to communicate these changes clearly and perhaps even temper the pace of renaming by holding off until results are strongly corroborated. Some stability measures (like proposing nomenclatural conservation of widely used names even if they are technically nested in another group) can mitigate the impact on the broader community.
The pathway can be activated by a range of signals, including hormones, growth factors and components of the extracellular matrix (ECM). It is stimulated by binding of an extracellular ligand to a receptor tyrosine kinase (RTK) in the plasma membrane, causing receptor dimerization and cross-phosphorylation of tyrosine residues in the intracellular domains. The regulatory subunit p85 binds to phosphorylated tyrosine residues on the activated receptor via its Src homology 2 (SH2) domain. It then recruits the catalytic subunit p110 to form the fully active PI3K enzyme. Alternatively, adaptor molecule Grb2 binds to phospho-YXN motifs of the RTK and recruits p85 via Grb2-associated binding (GAB) scaffold protein. The p110 subunit can also be recruited independently of p85. For example, Grb2 can also bind the Ras-GEF Sos1, leading to activation of Ras. Ras-GTP then activates the p110 subunit of PI3K. Other adaptor molecules such as insulin receptor substrate (IRS) can also activate p110.
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。
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.