lyophilized powder raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-11-14. Anything still debated is marked as such rather than presented as settled.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
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 heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
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.
| 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. 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.
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.
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.
== Zoological usage == The integument of an organ in zoology typically would comprise membranes of connective tissue such as those around a kidney or liver. In referring to the integument of an animal, the usual sense is its skin and its derivatives: the integumentary system, where "integumentary" is a synonym of "cutaneous". In arthropods, the integument, or external "skin", consists of a single layer of epithelial ectoderm from which arises the cuticle, an outer covering of chitin, the rigidity of which varies as per its chemical composition. The molting of this cuticle and growing of a larger one as part of their growth cycle is characteristic for arthropods, and ecdysozoa in general.
==== As defendant ==== Monster Energy has occasionally been on the other side of copyright infringement lawsuits. For example, in August 2012, the Beastie Boys filed a lawsuit against the company for copyright infringement over Monster's use of their music played by Z-Trip in an online campaign. In 2014, a jury found Monster Beverage Corporation had infringed on Beastie Boys' copyright by using songs without permission, and owed the group $1.7 million.
April 30: Decree dismissing "useless" women (prostitutes) from armies. June 10–11: Decree on communal property division, allowing women and men over 21 to participate and vote in assemblies. June 24: Constitution of Year I denies women citizenship rights. June 28: Decree on annual aid for children, the elderly, and the indigent, mandating districts to provide secret housing for pregnant girls to give birth, with confidentiality and funded care (children born become wards of the nation); free childbirth care for indigent women, mandatory breastfeeding (except for medical reasons) for indigent families, with financial aid. August 24: Married women's annuities and interest remain theirs but are paid directly to husbands. October 30: Decree banning women's political clubs and societies. December 19: Decree mandating state-organized compulsory primary education for girls and boys aged 6–8. 1794
Sources: en.wikipedia.org
At midnight between 17 and 18 April 1980, the country was granted independence by Britain under the name of Zimbabwe. A new national flag was adopted, the draft for which had been handed to the Minister of Public Works Richard Hove by an unspecified designer. The initial design did not include the Zimbabwe Bird, which was added at the suggestion of Cederic Herbert, who pointed out its uniqueness and history. The final draft went through the approval of the Prime Minister-elect Robert Mugabe. The adoption of the new flag coincided with the swearing-in of Canaan Banana as the country's new president. The Zimbabwe Bird, used on every flag since 1968, is based on a statue discovered from the medieval ruined city of Great Zimbabwe in the country's south-east.
=== Pesticides === Although the of lead arsenic-containing pesticides has long been stopped, large areas land remain contaminated. Some arsenic-based pesticides still exist. Chromated copper arsenate has been registered for use in the United States since the 1940s as a wood preservative, protecting wood from insects and microbial agents. In 2003, manufacturers of chromated copper arsenate initiated a voluntary recall of residential wood treated with the chemical. The Environmental Protection Agency Act 2008 final report stated that chromated copper arsenate is still approved for use in nonresidential applications, such as in marine facilities (pilings and structures), utility poles, and sand highway structures.
In the final stage of elongation, called translocation, the deacylated tRNA (in the P site) and the dipeptidyl-tRNA (in the A site) along with its corresponding codons move to the E and P sites, respectively, and a new codon moves into the A site. This process is catalyzed by elongation factor G (EF-G). The deacylated tRNA at the E site is released from the ribosome during the next A-site occupation by an aminoacyl-tRNA again facilitated by EF-Tu. The ribosome continues to translate the remaining codons on the mRNA as more aminoacyl-tRNA bind to the A site, until the ribosome reaches a stop codon on mRNA(UAA, UGA, or UAG). The translation machinery works relatively slowly compared to the enzyme systems that catalyze DNA replication. Proteins in bacteria are synthesized at a rate of only 18 amino acid residues per second, whereas bacterial replisomes synthesize DNA at a rate of 1000 nucleotides per second. This difference in rate reflects, in part, the difference between polymerizing four types of nucleotides to make nucleic acids and polymerizing 20 types of amino acids to make proteins. Testing and rejecting incorrect aminoacyl-tRNA molecules takes time and slows protein synthesis. In bacteria, translation initiation occurs as soon as the 5' end of an mRNA is synthesized, and translation and transcription are coupled. This is not possible in eukaryotes because transcription and translation are carried out in separate compartments of the cell (the nucleus and cytoplasm).
Sources: en.wikipedia.org
10 mm (0.4 in) – it has well-defined gill arches and has a thin ventral finfold 21 mm (0.8 in) – dorsal and pelvic fin buds appear 33 mm (1.3 in) – embryo has protruding eyes and well-developed gill filaments 43 mm (1.7 in) – it has lost its translucency and develops slits in the egg case, allowing fluid exchange from surrounding seawater and the interior 58 mm (2.3 in) – the finfold starts to decay 66 mm (2.6 in) – the finfold and gill filaments are reduced or absent 74 mm (2.9 in) – external appearance is complete but yolk sac is still being absorbed 100–110 mm (3.9–4.3 in) – hatching
In archaea such as Thermoplasma acidophilum, all the α and all the β subunits are identical, whereas eukaryotic proteasomes such as those in yeast contain seven distinct types of each subunit. In mammals, the β1, β2, and β5 subunits are catalytic; although they share a common mechanism, they have three distinct substrate specificities considered chymotrypsin-like, trypsin-like, and peptidyl-glutamyl peptide-hydrolyzing (PHGH). Alternative β forms denoted β1i, β2i, and β5i can be expressed in hematopoietic cells in response to exposure to pro-inflammatory signals such as cytokines, in particular, interferon gamma. The proteasome assembled with these alternative subunits is known as the immunoproteasome, whose substrate specificity is altered relative to the normal proteasome. Recently an alternative proteasome was identified in human cells that lack the α3 core subunit. These proteasomes (known as the α4-α4 proteasomes) instead form 20S core particles containing an additional α4 subunit in place of the missing α3 subunit. These alternative 'α4-α4' proteasomes have been known previously to exist in yeast. Although the precise function of these proteasome isoforms is still largely unknown, cells expressing these proteasomes show enhanced resistance to toxicity induced by metallic ions such as cadmium. The peptides that are formed by the 20S core have recently been shown to act as important metabolites for both programmed cell death and for immunity.
Creatine methyl ester is the methyl ester derivative of the amino acid creatine. It can be prepared by the esterification of creatine with methanol. By undergoing an esterification process with methanol, this compound seeks to enhance creatine's absorption rate in the body. Creatine esters, like creatine methyl ester, have been studied for their potential to improve bioavailability when compared to standard creatine monohydrate.
"inability to reconcile the Allies' declared policy of self-determination with the Balfour Declaration, giving rise to a sense of betrayal and intense anxiety for their future"; "misapprehension of the true meaning of the Balfour Declaration and forgetfulness of the guarantees determined therein, due to the loose rhetoric of politicians and the exaggerated statements and writings of interested persons, chiefly Zionists"; and "Zionist indiscretion and aggression since the Balfour Declaration aggravating such fears". British public and government opinion became increasingly unfavourable to state support for Zionism; even Sykes had begun to change his views in late 1918. In February 1922 Churchill telegraphed Samuel, who had begun his role as High Commissioner for Palestine 18 months earlier, asking for cuts in expenditure and noting:In both Houses of Parliament there is growing movement of hostility, against Zionist policy in Palestine, which will be stimulated by recent Northcliffe articles. I do not attach undue importance to this movement, but it is increasingly difficult to meet the argument that it is unfair to ask the British taxpayer, already overwhelmed with taxation, to bear the cost of imposing on Palestine an unpopular policy. Following the issuance of the Churchill White Paper in June 1922, the House of Lords rejected a Palestine Mandate that incorporated the Balfour Declaration by 60 votes to 25, following a motion issued by Lord Islington.
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。
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.