合成七肽 is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-12-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
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.
| 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 |
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。
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。
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
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. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
== Chain standards == Standards organizations (such as ANSI and ISO) maintain standards for design, dimensions, and interchangeability of transmission chains. For example, the following table shows data from ANSI standard B29.1-2011 (precision power transmission roller chains, attachments, and sprockets) developed by the American Society of Mechanical Engineers (ASME). See the references for additional information.
Methanol – Caused by the demethylation of pectins in the must by enzymes of the yeast. More commonly found in red wines than white but only in very small amounts between 20 and 200 mg/L. Fusel oils – Formed by the decomposition of amino acids by the yeast. This includes 2,3-butanediol which is formed by yeast that are consuming diacetyl, the compound that gives Chardonnay and other wines a "buttery" aroma, reducing it first to acetoin and then to the more neutral-smelling 2,3-butanediol. Many beer and winemakers who have a wine with too much "butteriness" will often "pitch" fresh yeast cultures into the no longer fermenting tank so that the yeast will consume the diacetyl and reduce the aroma. Succinic acid – Like glycerol, this is often formed early in fermentation. Usually found in concentrations of 500–1200 mg/L, it is a minor acid in the overall acidity of wine. Acetic acid – Considered a main component of volatile acidity that can make a wine taste unbalanced and overly acidic. While acetic acid is the main volatile acid produced by yeast, trace amounts of butyric, formic and propionic acids can also be formed depending on the yeast strain. Most countries have wine laws setting the legal limit of volatile acidity, usually expressed as acetic acid, to 1200–2000 mg/L. Acetic acid can also lead to the development of the wine fault ethyl acetate which is characterized by a "nail polish remover" smell. However, small amounts of acetic acid are actually beneficial for the yeast as they use them to synthesis lipids in the cell membrane.
Compared with most other classes of natural compounds, alkaloids are characterized by a great structural diversity. There is no uniform classification. Initially, when knowledge of chemical structures was lacking, botanical classification of the source plants was relied on. This classification is now considered obsolete. More recent classifications are based on similarity of the carbon skeleton (e.g., indole-, isoquinoline-, and pyridine-like) or biochemical precursor (ornithine, lysine, tyrosine, tryptophan). However, they require compromises in borderline cases; for example, nicotine contains a pyridine fragment from nicotinamide and a pyrrolidine part from ornithine and therefore can be assigned to both classes. Alkaloids are often divided into the following major groups:
The thymus may contain cysts, usually less than 4 cm in diameter. Thymic cysts are usually detected incidentally and do not generally cause symptoms. Thymic cysts can occur along the neck or in the chest (mediastinum). Cysts usually just contain fluid and are lined by either many layers of flat cells or column-shaped cells. Despite this, the presence of a cyst can cause problems similar to those of thymomas, by compressing nearby structures, and some may contact internal walls (septa) and be difficult to distinguish from tumours. When cysts are found, investigation may include a workup for tumours, which may include CT or MRI scan of the area the cyst is suspected to be in.
Sources: en.wikipedia.org
Chloroplasts have their own ribosomes, which they use to synthesize a small fraction of their proteins. Chloroplast ribosomes are about two-thirds the size of cytoplasmic ribosomes (around 17 nm vs 25 nm). They take mRNAs transcribed from the chloroplast DNA and translate them into protein. While similar to bacterial ribosomes, chloroplast translation is more complex than in bacteria, so chloroplast ribosomes include some chloroplast-unique features. Small subunit ribosomal RNAs in several Chlorophyta and euglenid chloroplasts lack motifs for Shine-Dalgarno sequence recognition, which is considered essential for translation initiation in most chloroplasts and prokaryotes. Such loss is also rarely observed in other plastids and prokaryotes. An additional 4.5S rRNA with homology to the 3' tail of 23S is found in "higher" plants.
The French pressure cell press, or French press, is an apparatus used in biological experimentation to disrupt the plasma membrane of cells by passing them through a narrow valve under high pressure. The French press can also be used for disintegration of chloroplasts, homogenates of animal tissue, and other biological particles. It is capable of disrupting cell walls while leaving the cell nucleus undisturbed. The French press was invented by Charles Stacy French of the Carnegie Institution of Washington. The press uses an external hydraulic pump to drive a piston within a larger cylinder that contains the liquid sample. The highly pressurized sample is then squeezed past a needle valve. As the sample passes through the valve, the fluid experiences shear stress and decompression, causing cellular disruption. The major components of a French press are made of stainless steel to prevent sample contamination. A French press is commonly used to break the resilient plasma membrane and cell walls of bacteria and other microorganisms for isolation of proteins and other cellular components. The disruption of cells in a French press generates 'inside-out' membrane vesicles which are required for many in vitro biochemical assays. The cell is typically chilled overnight before use to preserve enzymatic activities. Disadvantages of the press include that it is not well suited for processing large sample volumes, and is somewhat difficult to operate as a result of the large weight of the assembly (about 14 kg).
In many-body potentials, the potential energy includes the effects of three or more particles interacting with each other. In simulations with pairwise potentials, global interactions in the system also exist, but they occur only through pairwise terms. In many-body potentials, the potential energy cannot be found by a sum over pairs of atoms, as these interactions are calculated explicitly as a combination of higher-order terms. In the statistical view, the dependency between the variables cannot in general be expressed using only pairwise products of the degrees of freedom. For example, the Tersoff potential, which was originally used to simulate carbon, silicon, and germanium, and has since been used for a wide range of other materials, involves a sum over groups of three atoms, with the angles between the atoms being an important factor in the potential. Other examples are the embedded-atom method (EAM), the EDIP, and the Tight-Binding Second Moment Approximation (TBSMA) potentials, where the electron density of states in the region of an atom is calculated from a sum of contributions from surrounding atoms, and the potential energy contribution is then a function of this sum.
The Federal Republic of Yugoslavia ended in 2003 after the Federal Assembly of Yugoslavia voted to enact the Constitutional Charter of Serbia and Montenegro, which established the State Union of Serbia and Montenegro. As such, the name Yugoslavia was consigned to history. A growing independence movement in Montenegro, led by Milo Đukanović, caused the new constitution of Serbia and Montenegro to include a clause allowing for a referendum on the question of Montenegrin independence after three years. In 2006, the referendum was called, passing by a narrow margin. This led to the dissolution of the State Union of Serbia and Montenegro and the establishment of the independent republics of Serbia and Montenegro, turning Serbia into a landlocked country. Some consider this the last act in the breakup of Yugoslavia.
The left heart has two chambers: the left atrium and the left ventricle, separated by the mitral valve. The left atrium receives oxygenated blood back from the lungs via one of the four pulmonary veins. The left atrium has an outpouching called the left atrial appendage. Like the right atrium, the left atrium is lined by pectinate muscles. The left atrium is connected to the left ventricle by the mitral valve. The left ventricle is much thicker as compared with the right, due to the greater force needed to pump blood to the entire body. Like the right ventricle, the left also has trabeculae carneae, but there is no moderator band. The left ventricle pumps blood to the body through the aortic valve and into the aorta. Two small openings above the aortic valve carry blood to the heart muscle; the left coronary artery is above the left cusp of the valve, and the right coronary artery is above the right cusp.
Sources: en.wikipedia.org
Hyaluronidase increases tissue permeability to accelerate the absorption of other enzymes into tissues. Some snake venoms carry fasciculins, like the mambas (Dendroaspis), which inhibit cholinesterase to make the prey lose muscle control.
== Uses == Secretin is used in diagnostic tests for pancreatic function; secretin is injected and the pancreatic output can then be imaged with magnetic resonance imaging, a noninvasive procedure, or secretions generated as a result can gathered either through an endoscope or through tubes inserted through the mouth, down into the duodenum. A recombinant human secretin has been available since 2004 for these diagnostic purposes. There were problems with the availability of this agent from 2012 to 2015.
==== Combination formulations ==== Adapalene/benzoyl peroxide (CD-0271/CD-1579; Epiduo; GK-530G; Tactuo; TactuPump) – combination of adapalene (retinoid) and benzoyl peroxide (undefined mechanism of action) Adapalene/benzoyl peroxide/clindamycin phosphate (Cabtreo; IDP-126) – combination of adapalene (retinoid), benzoyl peroxide (undefined mechanism of action), and clindamycin phosphate (lincosamide antibiotic) Benzoyl peroxide/clindamycin (Duac) – combination of benzoyl peroxide (undefined mechanism of action) and clindamycin (lincosamide antibiotic) Benzoyl peroxide/clindamycin low dose (Acanya; BenzaClin; Clin-BPO; Onexton) – combination of benzoyl peroxide (undefined mechanism of action) and clindamycin (lincosamide antibiotic) Benzoyl peroxide/tretinoin – combination of benzoyl peroxide (undefined mechanism of action) and tretinoin (retinoid) Clindamycin/tretinoin (Acnatac; Acnex; CLin-RA; Ziana) – combination of clindamycin (lincosamide antibiotic) and tretinoin (retinoid) Ethinylestradiol/drospirenone low-dose (Yasmin, Yaz) – combination of ethinylestradiol (estrogen) and drospirenone (progestogen) and a combined oral contraceptive Ethinylestradiol/drospirenone/levomefolic acid (BAY98-7071; Beyaz; Safyral; Yasmin Plus; Yaz Flex Plus; Yaz Plus) – combination of ethinylestradiol (estrogen), drospirenone (progestogen), and levomefolic acid (vitamin B9) and a combined oral contraceptive
The two substrates of this enzyme are (S)-malic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are oxaloacetic acid, 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 (S)-malate:NADP+ oxidoreductase. Other names in common use include NADP+-malic enzyme, NADP+-malate dehydrogenase, malic dehydrogenase (nicotinamide adenine dinucleotide phosphate), malate NADP+ dehydrogenase, NADP+ malate dehydrogenase, NADP+-linked malate dehydrogenase, and malate dehydrogenase (NADP+). This enzyme participates in pyruvate metabolism and carbon fixation. This enzyme has at least one effector, hn.
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.
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.