This is a working overview of synthetic heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
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.
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.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
=== Neurocognitive safety === Studies of SSRIs in patients with major psychiatric disorders prove that SSRIs are potentially associated with certain neurocognitive adverse effects such as anxiety, akathisia, hypomania, changes in mood, or suicidal thought. No study on the effects of SSRIs in men with PE has been done. McMahon's study in 2012 showed that dapoxetine has no effect on mood and is not associated with anxiety or suicidality.
The two substrates of this enzyme are dihydrobunolol and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are bunolol, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (+/−)-5-[(tert-butylamino)-2'-hydroxypropoxy]-1,2,3,4-tetrahydro-1-naphthol:NADP+ oxidoreductase. This enzyme is also termed bunolol reductase.
Viruses are often modified so they can be used as vectors for inserting genetic information into other organisms. This process is called transduction and if successful the recipient of the introduced DNA becomes a GMO. Different viruses have different efficiencies and capabilities. Researchers can use this to control for various factors; including the target location, insert size, and duration of gene expression. Any dangerous sequences inherent in the virus must be removed, while those that allow the gene to be delivered effectively are retained. While viral vectors can be used to insert DNA into almost any organism it is especially relevant for its potential in treating human disease. Although primarily still at trial stages, there has been some successes using gene therapy to replace defective genes. This is most evident in curing patients with severe combined immunodeficiency rising from adenosine deaminase deficiency (ADA-SCID), although the development of leukemia in some ADA-SCID patients along with the death of Jesse Gelsinger in a 1999 trial set back the development of this approach for many years. In 2009, another breakthrough was achieved when an eight-year-old boy with Leber's congenital amaurosis regained normal eyesight and in 2016 GlaxoSmithKline gained approval to commercialize a gene therapy treatment for ADA-SCID. As of 2018, there are a substantial number of clinical trials underway, including treatments for hemophilia, glioblastoma, chronic granulomatous disease, cystic fibrosis and various cancers.
Electrical stimulation using implantable devices came into modern usage in the 1980s, and its techniques and applications have continued to develop and expand. These are methods where an operation is required to position an electrode. The stimulator, with the battery, similar to a pacemaker, may also be implanted, or may remain outside the body. In general, neuromodulation systems deliver electrical currents and typically consist of the following components: An epidural, subdural, or parenchymal electrode placed via minimally invasive needle techniques (so-called percutaneous leads) or an open surgical exposure to the target (surgical "paddle" or "grid" electrodes), or stereotactic implants for the central nervous system, and an implanted pulse generator (IPG). Depending on the distance from the electrode access point, an extension cable may also be added into the system. The IPG can have either a non-rechargeable battery needing replacement every 2–5 years (depending on stimulation parameters) or a rechargeable battery that is replenished via an external inductive charging system. Although most systems operate via delivery of a constant train of stimulation, there has recently been an emergence of so-called "feed-forward" stimulation, in which the device's activation is contingent on a physiological event, such as an epileptic seizure. In this circumstance, the device is activated and delivers a desynchronizing pulse to the cortical area that is undergoing an epileptic seizure.
Sources: en.wikipedia.org
If the person presents more than eight hours after the paracetamol overdose, then activated charcoal is not useful, and acetylcysteine is started immediately. In earlier presentations, charcoal can be given when the patient arrives and acetylcysteine is initiated while waiting for the paracetamol level results to return from the laboratory. In United States practice, intravenous (IV) and oral administration are considered to be equally effective and safe if given within 8 hours of ingestion. However, IV is the only recommended route in Australasian and British practice. Oral acetylcysteine is given as a 140 mg/kg loading dose followed by 70 mg/kg every four hours for 17 more doses, and if the patient vomits within 1 hour of dose, the dose must be repeated. Oral acetylcysteine may be poorly tolerated due to its unpleasant taste, odor, and its tendency to cause nausea and vomiting. If repeated doses of charcoal are indicated because of another ingested drug, then subsequent doses of charcoal and acetylcysteine should be staggered. Intravenous acetylcysteine is given as a continuous infusion over 20 hours for a total dose 300 mg/kg. Recommended administration involves infusion of a 150 mg/kg loading dose over 15 to 60 minutes, followed by a 50 mg/kg infusion over four hours; the last 100 mg/kg are infused over the remaining 16 hours of the protocol.
== Function == Enzyme-generated isopeptide bonds have two main biological purposes: signaling and structure. Biosignaling influences protein function, chromatin condensation, and protein-half life. The biostructural roles of isopeptide bonds include blood clotting (for wound healing), extracellular matrix upkeep, the apoptosis pathway, modifying micro-tubules, and forming pathogenic pili in bacteria. Isopeptide bonds contribute to the pathogenicity of Vibrio cholerae because the actin cross-linking domain (ACD) forms an intermolecular bond between the γ-carboxyl group of glutamate and the ε-amino group of lysine in actin. This process stops actin polymerization in the host cell.
The restaurant was founded in 1987 in Rosettenville, Johannesburg by Portuguese-born Fernando Duarte and South African-born Robert Brozin. Upon visiting a Portuguese Mozambican takeaway named Chickenland and trying the chicken with peri peri, they bought the restaurant for about 80,000 rand (equivalent to about £25,000 at the time). They renamed the restaurant Nando's after Fernando's firstborn son. By 1989, the restaurant had three outlets in Johannesburg and one in Portugal. Capricorn Ventures International acquired the chain in 1992. In that year, the first branch opened up in Ealing Common where once stood a branch of Midland Bank. In 2010, Advertising Age magazine named Nando's one of the world's top 30 hottest marketing brands alongside Tata Nano, MTN and Natura. During the same year, the success of Nando's in the U.K. led The Guardian to write that Nando's was a modern restaurant brand that had "changed the face of British fast food." Nando's 1,000th store worldwide opened in 2012. As of July 2014, the Nando's restaurant group was owned by South African businessman Dick Enthoven and his family, through the Luxembourg-domiciled company Yellowwoods. Enthoven's son Robby Enthoven, who took over running the restaurants in 1993, was responsible for expanding the Nando's chain in the United Kingdom. In 2018, American-based recruitment website Indeed named Nando's as the UK's sixth best private sector employer based on millions of employee ratings and reviews.
Glycerol is a stable preserving agent for botanical extracts that, when utilized in proper concentrations in an extraction solvent base, does not allow inverting or reduction-oxidation of a finished extract's constituents, even over several years. Both glycerol and ethanol are viable preserving agents. Glycerol is bacteriostatic in its action, and ethanol is bactericidal in its action.
Jessie McTavish, a nurse convicted and then controversially cleared of the 1974 murder of an 80-year-old patient with insulin, has been identified as the likely inspiration for Norris. She had worked at Ruchill Hospital in Glasgow, less than a mile from where Norris grew up. She had been released on appeal after her defence team successfully argued that the trial judge had inadvertently misled the jury in his final summing up, even though the appeal court judges said that it was something a "few words could have cured" and that there was enough evidence to support the prosecution. Norris's personal tutor at university gave a specific talk to him and other students on her case on 11 January 2001, a year before Norris committed his first attack, in which Norris used the same method as McTavish had been accused of using. Norris was tasked with "reviewing" her conduct, and in doing so, he would have learned that insulin is the perfect weapon for murder because it leaves the blood very quickly. Just like Norris, McTavish had 'predicted' the exact time when a healthy patient would die. She was able to continue her career in nursing after she was released on appeal. Norris had notably also attended lectures in 1999 on diabetes and the treatment of diabetic patients with insulin, where he learned about the consequences of blood sugars being too high or too low.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
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。