If you have been reading about synthetic heptapeptide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-08-08. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
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.
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.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
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.
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.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
=== NIA T32 Training Program for Research Scientists in the Biology of Aging === The NIA T32 Training Program for Research Scientists in the Biology of Aging is one of the nation's premier institutional training programs dedicated to preparing the next generation of leaders in geroscience. Established through support from the National Institute on Aging (NIA), the program provides rigorous multidisciplinary research training for both predoctoral (PhD and MD/PhD) students and postdoctoral fellows pursuing careers in the basic, translational, and clinical biology of aging. For more than three decades, the program has trained investigators who have gone on to become independent scientists, faculty members, and leaders in academia, government, and industry, significantly contributing to advances in aging biology and age-related disease research. The overarching goal of the training program is to develop independent investigators capable of translating discoveries in the fundamental biology of aging into interventions that improve healthspan and reduce the burden of age-associated diseases. Trainees receive individualized, mentor-guided research experiences that integrate molecular, cellular, organismal, and translational approaches to understanding the mechanisms that drive biological aging. The curriculum emphasizes the principles of geroscience—the concept that targeting the biological processes of aging can simultaneously delay or prevent multiple chronic diseases—providing trainees with a broad scientific foundation while encouraging innovative, interdisciplinary research.
The penultimate process is called conching. A conche is a container filled with metal beads, which act as grinders. The refined and blended chocolate mass is kept in a liquid state by frictional heat. Before conching, chocolate has an uneven and gritty texture. The conching process produces cocoa and sugar particles smaller than the tongue can detect (typically around 20 μm) and reduces rough edges, hence the smooth feel in the mouth. The length of the conching process determines the final smoothness and quality of the chocolate. After the process is complete, the chocolate mass is stored in tanks heated to about 45–50 °C (113–122 °F) until final processing. After conching, chocolate is tempered to crystallize a small amount of cocoa butter. Cocoa butter is a polymorphic fat with six different crystal forms, but only one of them—Form V—gives chocolate its characteristic snap, gloss, and stable texture. Tempering eliminates the undesirable crystal forms and promotes the formation of Form V. After chocolate has been tempered, it is molded into different shapes, including chocolate bars and chocolate chips.
=== Centrifugal === In centrifugal FFF, the separation field is generated via a centrifugal force. The channel takes the form of a ring, which spins at rotation speeds which can be programmed during the run. The flow and sample are pumped into the channel and centrifuged, allowing the operator to resolve the particles by mass (size and density). The advantage of centrifugal FFF lies in the high size resolution that can be achieved by varying the force applied, since particle size is proportional to particle mass to the third power. The unique advantage presented by centrifugal FFF comes from the techniques capability for high resolution given sufficient buoyant density. This allows for the separation of particles with only a 5% difference in size. Centrifugal FFF has the advantage that particles and macromolecules can be separated by particle density, rather than just particle size. In this instance, two identically sized gold and silver nanoparticles can be separated into two peaks, according to differences in density in the gold and silver nanoparticles, In AF4 separations, the ratio of mass to time is 1:1. With the addition of the third parameter of density to centrifugal FFF, this produces a ratio more akin to mass:time to the power of three. This results in a significantly larger distinction between peaks and result in a greatly improved resolution. This can be particularly useful for novel products, such as composite materials and coated polymers containing nanoparticles, i.e. particles which may not vary in size but which do vary in density.
Glial cells are the supporting cells of the neurons. The three types of glial cells are astrocytes, oligodendrocytes, and ependymal cells, known collectively as macroglia, and the smaller scavenger cells known as microglia. Glial stem cells are found in all parts of the adult brain. Glial cells greatly outnumber neurons and apart from their supporting role to neurons, glia – astrocytes in particular have been acknowledged as being able to communicate with neurons involving a signalling process similar to neurotransmission called gliotransmission. They cannot produce an action potential as generated by a neuron but in their large numbers they can produce chemicals expressing excitability that exert an influence on neural circuitry. The star-like shape of the astrocyte allows contact with a great many synapses. Microglia account for about around 5–10% of cells found within the brain.
Sources: en.wikipedia.org
=== Cardiovascular disease === Cardiovascular disease can present itself in many different forms, from cardiomyopathy to peripheral arterial disease, and heart disease remains a key threat to human health. While there are means of therapy to both prevent and cure cardiovascular diseases, many drugs are unavailable for clinical use due to severe side effects in addition to high toxicity levels. However, in the past decade, sv-LAAOs have shown promise in affecting platelet aggregation. It has been proposed that hydrogen peroxide is considered to play a significant role regarding the enzymes ability to both cause and prevent this platelet aggregation. With this knowledge, it appears that sv-LAAOs could be evaluated as a potential cardiovascular disease therapeutic because of their biological potency.
Nickel is a silvery-white metal with a slight golden tinge that takes a high polish. It is one of only four elements that are ferromagnetic at or near room temperature; the others are iron, cobalt and gadolinium. Its Curie temperature is 355 °C (671 °F), meaning that bulk nickel is non-magnetic above this temperature. The unit cell of nickel is a face-centered cube; it has lattice parameter of 0.352 nm, giving an atomic radius of 0.124 nm. This crystal structure is stable to pressures of at least 70 GPa. Nickel is hard, malleable and ductile, and has a relatively high electrical and thermal conductivity for transition metals. The high compressive strength of 34 GPa, predicted for ideal crystals, is never obtained in the real bulk material due to formation and movement of dislocations. However, it has been reached in Ni nanoparticles.
The small vessels in the skin affected are located in the superficial dermis and include arterioles (small arteries carrying blood to capillaries), capillaries, and venules (small veins receiving blood from capillaries). In general, immune complexes deposit in vessel walls leading to activation of the complement system. C3a and C5a, proteins produced from the complement system, attract neutrophils to the vessels. Once activated, neutrophils then release preformed substances, including enzymes, causing damage to vessel tissue. Evidence of this process can be seen with a sample of removed skin tissue, or biopsy, viewed under a microscope. Neutrophils are seen surrounding blood vessels and their debris within vessel walls, causing fibrinoid necrosis. This finding on histological examination is termed "leukocytoclastic vasculitis". Considering the wide range of potential causes leading to cutaneous small vessel vasculitis, there are subtle variations in the underlying pathophysiology for each cause. For example, medications are metabolized to smaller molecules that can attach to proteins in the blood or vessel walls. The immune system senses these altered proteins as foreign and produces antibodies in efforts to eliminate them from the body. A similar process occurs with infectious agents, such as bacteria, in which antibodies target microbial components.
== Clinical significance == There are many diseases where failure to adequately absorb iron contributes to iron deficiency and iron deficiency anemia. The treatment will depend on the hepcidin levels that are present, as oral treatment will be unlikely to be effective if hepcidin is blocking enteral absorption; in these cases, parenteral iron treatment would be appropriate. Studies have found that measuring hepcidin would help establish the optimal treatment for a patient, but as this is not widely available, C-reactive protein (CRP) is used as a surrogate marker. Chronic alcohol consumption can lead to excess iron accumulation in the liver, which may contribute to the development of alcoholic liver disease. Chronic alcohol use may increase iron accumulation by inhibiting hepcidin gene expression. The main mechanisms appear to be increasing oxidative stress through its metabolite acetaldehyde, and by inhibiting the release of interleukin 6 (IL-6) from macrophages; each of these actions reduce the expression and DNA-binding activity of the transcription factor C/EBPα, which would otherwise stimulate hepcidin expression. Beta thalassemia, one of the most common congenital anemias, arises from partial or complete failure to synthesize beta-globin, a component of hemoglobin. Excessive iron absorption is one of the main features of beta thalassemia and can lead to severe morbidity and mortality.
=== Carboxyl biotinylation === Carboxyl groups are found on the C-terminal ends of proteins and on glutamate and aspartate amino acid side chains. Biotinylation reagents that target carboxyl groups do not have a carboxyl-reactive moiety per se but instead rely on a carbodiimide crosslinker such as EDC to bind the primary amine on the biotinylation reagents to the carboxyl group on the target protein. Biotinylation at carboxyl groups occur at pH 4.5–5.5. To prevent crossreactivity of the crosslinker with buffer constituents, buffers should not contain primary amines (e.g., Tris, glycine) or carboxyls (e.g., acetate, citrate); MES buffer is an ideal choice.
Sources: en.wikipedia.org
Transmembrane AMPA receptor regulatory proteins (TARPs) are a family protein that associate with AMPA receptors and control their trafficking and conductance. CACNG2 (Stargazin) is one such protein and is found to bind AMPA receptors in the perisynaptic and postsynaptic regions. The role of stargazin in trafficking between the perisynaptic and postsynaptic regions remains unclear; however, stargazin is essential for immobilizing AMPA receptors in the PSD by interacting with PSD-95. PSD-95 stabilizes AMPA receptors to the synapse and disruption of the stargazin-PSD-95 interaction suppressed synaptic transmission.
The study of plants is vital because they underpin almost all animal life on Earth by generating a large proportion of the oxygen and food that provide humans and other organisms with aerobic respiration with the chemical energy they need to exist. Plants, algae and cyanobacteria are the major groups of organisms that carry out photosynthesis, a process that uses the energy of sunlight to convert water and carbon dioxide into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells. As a by-product of photosynthesis, plants release oxygen into the atmosphere, a gas that is required by nearly all living things to carry out cellular respiration. In addition, they are influential in the global carbon and water cycles and plant roots bind and stabilise soils, preventing soil erosion. Plants are crucial to the future of human society as they provide food, oxygen, biochemicals, and products for people, as well as creating and preserving soil. Historically, all living things were classified as either animals or plants and botany covered the study of all organisms not considered animals. Botanists examine both the internal functions and processes within plant organelles, cells, tissues, whole plants, plant populations and plant communities. At each of these levels, a botanist may be concerned with the classification (taxonomy), phylogeny and evolution, structure (anatomy and morphology), or function (physiology) of plant life.
The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). Together with hydrogen they constitute group 1, which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in them having very similar characteristic properties. Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. They can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation by atmospheric moisture and oxygen (and in the case of lithium, nitrogen). Because of their high reactivity, they must be stored under oil to prevent reaction with air, and are found naturally only in salts and never as the free elements. Caesium, the fifth alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.
=== Germany === A ban on absinthe was enacted in Germany on 27 March 1923. In addition to banning the production of commercial trade in absinthe, the law went so far as to prohibit the distribution of printed matter that provided details of its production. The original ban was lifted in 1981, but the use of Artemisia absinthium as a flavouring agent remained prohibited. On 27 September 1991, Germany adopted the European Community's standards of 1988, which effectively re-legalised absinthe.
Although life is very sparse at these depths, black smokers are the centers of entire ecosystems. Sunlight is nonexistent, so many organisms, such as archaea and extremophiles, convert the heat, methane, and sulfur compounds provided by black smokers into energy through a process called chemosynthesis. More complex life forms, such as clams and tubeworms, feed on these organisms. The organisms at the base of the food chain also deposit minerals into the base of the black smoker, therefore completing the life cycle. A species of phototrophic bacterium has been found living near a black smoker off the coast of Mexico at a depth of 2,500 m (8,200 ft). No sunlight penetrates that far into the waters. Instead, the bacteria, part of the Chlorobiaceae family, use the faint glow from the black smoker for photosynthesis. This is the first organism discovered in nature to exclusively use a light other than sunlight for photosynthesis. New and unusual species are constantly being discovered in the neighborhood of black smokers. The Pompeii worm Alvinella pompejana, which is capable of withstanding temperatures up to 80 °C (176 °F), was found in the 1980s, and the scaly-foot gastropod (Chrysomallon squamiferum) was first found in 2001 during an expedition to the Indian Ocean's Kairei hydrothermal vent field. The latter uses iron sulfides (pyrite and greigite) for the structure of its dermal sclerites (hardened body parts), instead of calcium carbonate.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。