合成七肽 comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-10-23. Numbers and descriptions here follow the published literature rather than marketing material.
Semax 是人工设计的七肽,序列为 Met-Glu-His-Phe-Pro-Gly-Pro,骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性,同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应,Semax 属于这一路线。鼻内给药是其主要使用方式,俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上,样本规模与终点设置同西方试验惯例存在差异,国际同行对其临床证据的强度看法不一。
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 |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构,不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
== Taxonomy == The genus Ophiophagus was proposed by Günther in 1864 in place of Hamadryas, as the genus Hamadryas was already used for the cracker butterflies. The name is derived from its propensity to eat snakes. Ophiophagus hannah was accepted as the valid name for the king cobra by Charles Mitchill Bogert in 1945 who argued that it differs significantly from Naja species. It has been suggested that three more king cobra species exist in addition to O. hannah, namely the Sunda king cobra (O. bungarus), the Western Ghats king cobra (O. kaalinga), and the Luzon king cobra (O. salvatana). These distinct genetic lineages are geographically isolated and adapted to specific ecological regions.
==== Insulin ==== In October 1920, Frederick Banting took interest in carbohydrate metabolism while preparing a talk he was to give his physiology students at Western University in London, Ontario. He encountered an article by Moses Barron which reported an autopsy of a patient whose pancreatic stone had obstructed the main pancreatic duct, but most of the islet cells had survived intact. Banting wrote a note on October 31 of that year describing his thinking: "Ligate pancreatic ducts of dog. Keep dogs alive till acini degenerate leaving Islets. Try to isolate the internal secretion of these to relieve glycosurea [sic]" On November 8, 1920, Banting met with John Macleod, a senior professor of physiology at the University of Toronto, to ask if he might mount a research project on the internal secretion of the pancreas. Banting lacked experience in physiological research and had superficial knowledge of the subject. Nonetheless, Macleod took some interest and accepted Banting's request to work in his lab. On account of what may have interested Macleod, Michael Bliss considers the following:Speculation is in order here and is permissible because we have some idea of Macleod's knowledge of the literature. Whether he and Banting were discussing grafting or extracting, what must have appealed to Macleod as "never having been tried before" was the idea of somebody experimenting with degenerated or atrophied pancreas.
Bidentate ligands bind to metal ions forming a chelate ring. Ligands of higher denticity form two or more chelate rings. Ethylenediamine, 2,2'-bipyridine, and 1,10-phenanthroline form C2N2M chelate rings. Just like in organic chemistry, 5- and 6-membered chelate rings predominate.
Sources: en.wikipedia.org
Propofol is highly protein-bound in vivo and is metabolized by conjugation in the liver. The half-life of elimination of propofol has been estimated to be between 2 and 24 hours. However, its duration of clinical effect is much shorter because propofol is rapidly distributed into peripheral tissues. When used for IV sedation, a single dose of propofol typically wears off within minutes. Onset is rapid, in as little as 15–30 seconds. Propofol's versatility allows it to be used for short or prolonged sedation, and general anesthesia; and unlike opioid medications, its use is not associated with nausea. These characteristics of rapid onset and recovery along with its amnestic effects have led to its widespread use for sedation and anesthesia.
===== Puromycin-associated nascent chain proteomics ===== Puromycin-associated nascent chain proteomics (PUNCH-P) uses a puromycin-biotin label to capture nascent polypeptides for MS. Though it does not disturb the cell process, it is less sensitive than other methods in detecting nascent peptides. In addition to these quantification methods, other MS based methods are being worked on.
This suggests that supermarket marketers should use this theory to their advantage by placing their temporary displays of products on the right-hand side to entice you to make an unplanned purchase. Furthermore, aisle ends are extremely popular with product manufacturers, who pay top dollar to have their products located there. These aisle ends are used to lure customers into making a snap purchase and to also entice them to shop down the aisle. The most obvious place supermarket layout influences consumers are at the checkout. Small displays of candy, magazines, and drinks are located at each checkout to tempt shoppers while they wait to be served.
Sources: en.wikipedia.org
spacer Also intergenic spacer (IGS) or non-transcribed spacer (NTS). Any sequence or region of non-coding DNA separating neighboring genes, whether transcribed or not. The term is used in particular to refer to the non-coding regions between the many repeated copies of the ribosomal RNA genes. See also intergenic region.
National Institute for Occupational Safety and Health has determined non-regulatory recommended exposure limits (RELs) of 1 μg/m3 for carbon nanotubes and carbon nanofibers as background-corrected elemental carbon as an 8-hour time-weighted average (TWA) respirable mass concentration. Although CNT caused pulmonary inflammation and toxicity in mice, exposure to aerosols generated from sanding of composites containing polymer-coated MWCNTs, representative of the actual end-product, did not exert such toxicity. As of October 2016, single-wall carbon nanotubes have been registered through the European Union's Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) regulations, based on evaluation of the potentially hazardous properties of SWCNT. Based on this registration, SWCNT commercialization is allowed in the EU up to 100 metric tons. The type of SWCNT registered through REACH is limited to the specific type of single-wall carbon nanotubes manufactured by OCSiAl, which submitted the application.
==== Commander of the Order of the British Empire (CBE) ==== Military Commodore Stephen David Roberts, Royal Navy, C032675H. Brigadier Vivienne Wendy Buck, 539464. Major General Julian Nicholas Edward Buczacki, 547874. Brigadier Matthew Timothy Cansdale, , 542140. Major General Darren Howard Crook, 538948. Colonel Lucy Margaret Giles, 533691. Colonel Michael Robert Smith, 533745. Air Commodore Catherine Clare Coton, Royal Air Force, 8032422G. Air Commodore Jonathan Moreton, Royal Air Force, 2636472F. Air Commodore Gerard Alan Opie, Royal Air Force, 5203734U. Civil Louise Elizabeth Alexander. Human Resources Director, HM Courts and Tribunals Service and Trustee, Rowland Hill Fund. For Public and Voluntary Service. Ellen Atkinson, LVO. Director, Constitution and Major Events, Cabinet Office. For Public Service. Mark Timothy Austin. Partner, Latham & Watkins. For services to the Economy. Henrietta Rosamund Clare Barkworth-Nanton. Co-Founder and Patron, The Joanna Simpson Foundation and Chair, Refuge. For services to People Affected by Domestic Abuse and Homicide. Charlotte Ann Beardmore. Executive Director, Professional Policy, The Society of Radiographers. For services to Radiography. Andrew James Bell. Lately Co-Founder and Chief Executive Officer, AJ Bell plc. For services to the Financial Sector. Professor Michaela Jane Benzeval. Professor of Longitudinal Research and Director of Understanding Society, University of Essex. For services to Social Science. Don Black, OBE. Lyricist. For services to Music. Stuart Christopher John Broad, MBE. Cricketer.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子,天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号,而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段,并在两端做了替换与延长,使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物,需要医生开具处方。多数其他国家把它当作研究化合物,不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
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.