peptide synthesis raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-06-16. Anything still debated is marked as such rather than presented as settled.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
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.
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 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。
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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.
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.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
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.
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。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
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.
== Censorship == During the conflict, the Taliban's intelligence agency, the General Directorate of Intelligence (GDI), ordered Afghan domestic media outlets not to cover areas targeted in recent Pakistani airstrikes. In some cases, intelligence personnel monitored media offices and newsroom operations to enforce the directive, and media outlets were warned against defying the order. Taliban intelligence officials also warned residents against publishing images or details of locations in Afghanistan targeted by Pakistani strikes. Afghan local sources stated that the Taliban were restricting access to information about their own casualties, as well as those among civilians. They added that only Taliban members were allowed to take images of affected areas and victims, making independent verification of casualties and damage difficult. According to the sources, even Taliban controlled media outlets were not allowed to photograph the sites and areas targeted by Pakistan's airstrikes, and there were no accurate statistics on the casualties of civilians and Taliban fighters. On 1 March, the Taliban suspended the broadcasts of Rah-e-Farda radio and television in Kabul, a channel affiliated with Mohammad Mohaqiq. The suspension was linked to remarks by Mohammad Mohaqiq, which reportedly criticized the Taliban's recent retaliatory attacks against Pakistan. On 5 March, the Taliban increased pressure on local media outlets, warning journalists not to report on attacks, particularly those targeting Taliban military sites.
The clitoral body (also known as the shaft of the clitoris) is a portion behind the glans that contains the union of the corpora cavernosa, a pair of sponge-like regions of erectile tissue that hold most of the blood in the clitoris during erection. It is homologous to the penile shaft in the male. The two corpora forming the clitoral body are surrounded by thick fibro-elastic tunica albuginea, a sheath of connective tissue. These corpora are separated incompletely from each other in the midline by a fibrous pectiniform septum – a comblike band of connective tissue extending between the corpora cavernosa. The clitoral body is also connected to the pubic symphysis by the suspensory ligament. The body of the clitoris is a bent shape, which makes the clitoral angle or elbow. The angle divides the body into the ascending part (internal) near the pubic symphysis and the descending part (external), which can be seen and felt through the clitoral hood.
== Differential diagnosis == The presentation of some cases is similar to that of Kearns–Sayre syndrome. Myoclonus epilepsy associated with ragged red fibers (MERRF) may be confused with MELAS as they both involve seizures, mental deterioration, and myopathy with ragged red fibers on biopsy. MERRF patients may also have hearing loss, visual disturbance secondary to optic atrophy, and short stature. The characteristic myoclonic seizure in MERRF may help to narrow diagnosis, but genetic testing should be considered to distinguish the two conditions. Leigh syndrome may also present with progressive neurological deterioration, seizures, and vomiting, mainly in young children.
== Uses == Trap baits containing dimethyl trisulfide have been used to capture Calliphora loewi and other blowflies. Dimethyl trisulfide has been found to be an effective cyanide antidote in a rodent model for cyanide poisoning both against subcutaneous potassium cyanide and inhaled hydrogen cyanide, converting cyanide to much less toxic thiocyanate. It is suggested that dimethyl trisulfide can be used in a mass casualty cyanide exposure setting. In conjunction with these studies, the LD50 of dimethyl trisulfide in CD-1 mice was found to be 598.5 mg/kg, which may be compared to the LD50 of potassium cyanide of 8.0 mg/kg.
The administration of feed supplements based on Chinese rhubarb or with prebiotics and probiotics had no discernible effect in clinical studies; there is only one small manufacturer's study on the activated charcoal-based absorber for indole in the large intestine (trade name Porus one), but this did not include any cats with kidney disease.
Sources: en.wikipedia.org
April 2022: The Central Licensing Authority, DCGI granted avipatdil manufacturing and marketing permission to Zuventus Healthcare Ltd under the brand name 'Oxyptadil', for treatment in patients with severe COVID-19 with ARDS.
== First published posthumously == De Profundis (written 1895–97, in Reading Gaol). Expurgated edition published 1905; suppressed portions 1913, expanded version in The Letters of Oscar Wilde (1962). The Rise of Historical Criticism (written while at college). First published in 1905 (Sherwood Press, Hartford, CT), privately printed. Reprinted in Miscellanies, the last volume of the First Collected Edition (1908). The First Collected Edition (Methuen & Co., 14 volumes) appeared in 1908 and contained many previously unpublished works. The Second Collected Edition (Methuen & Co., 12 volumes) appeared in installments between 1909–11 and contained several other unpublished works. The Letters of Oscar Wilde (written 1868–1900). Published in 1962. Republished as The Complete Letters of Oscar Wilde (2000), with letters discovered since 1962 and new annotations by Merlin Holland. The Women of Homer (written 1876, while at college). First published in Oscar Wilde: The Women of Homer (2008) by the Oscar Wilde Society.
On the other hand, if the principal plane of the analyzer is along DOC then both the halves will be equally dark. Thus it is clear that if the analyzing Nicol is slightly disturbed from DOC then one half becomes brighter than the other. Hence by using the half shade device, one can measure the angle of rotation more accurately. Determination of specific rotation: In order to determine a specific rotation of an optically active substance (say, sugar), the polarimeter tube is first filled with pure water and the analyzer is adjusted for equal darkness (both the halves should be equally dark) point. The position of the analyzer is noted with the help of the scale. Now the polarimeter tube is filled with a sugar solution of known concentration and again the analyzer is adjusted in such a way that again the equally dark point is achieved. The position of the analyzer is again noted. The difference of the two readings will give the angle of rotation θ. Hence, a specific rotation S is determined as S = θ/LC, where L is the optical path length and C is concentration of the substance.
== Bibliography == Ackerman, A. Bernard; Almut Böer; Bruce Bennin; Geoffrey J. Gottlieb (2005). Histologic Diagnosis of Inflammatory Skin Diseases An Algorithmic Method Based on Pattern Analysis. Ardor Scribendi. ISBN 978-1-893357-25-9. Archived from the original on 21 April 2011. Moore, Keith L. et al. (2010) Clinically Oriented Anatomy 6th Ed
Sources: en.wikipedia.org
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.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
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。