ACTH(4-10) raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-10-08 and is reviewed periodically as new material appears.
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.
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.
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.
| 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 |
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
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.
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.
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。
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。
The categorization according to the specific function mainly include: exterior-releasing or exterior-resolving, heat-clearing, downward-draining, or precipitating wind-damp-dispelling, dampness-transforming, promoting the movement of water and percolating dampness or dampness-percolating, interior-warming, qi-regulating or qi-rectifying, dispersing food accumulation or food-dispersing, worm-expelling, stopping bleeding or blood-stanching, quickening the Blood and dispelling stasis or blood-quickening, transforming phlegm, stopping coughing and calming wheezing or phlegm-transforming and cough- and panting-suppressing, Spirit-quieting, calming the liver and expelling wind or liver-calming and wind-extinguishing orifice-opening supplementing which includes qi-supplementing, blood-nourishing, yin-enriching, and yang-fortifying, astriction-promoting or securing and astringing, vomiting-inducing, and substances for external application.
His son and successor died young; under two soldier-emperors, Nikephoros II (r. 963–969) and John I Tzimiskes (r. 969–976), the army claimed numerous military successes, including the conquest of Cilicia and Antioch, and a victory against Bulgaria and the Kievan Rus' in 971. John in particular was an effective soldier-emperor who introduced frontier military reforms and pursued successful fiscal and diplomatic policies.
Chemically, the most common oxidation states of iron are iron(II) and iron(III). Iron shares many properties with other transition metals, including the other group 8 elements, ruthenium and osmium. Iron forms compounds in a wide range of oxidation states, −2 to +7. Iron also forms many coordination complexes; some of them, such as ferrocene, ferrioxalate, and Prussian blue have substantial industrial, medical, or research applications. The body of an adult human contains about 4 grams (0.005% body weight) of iron, mostly in hemoglobin and myoglobin. These two proteins play essential roles in oxygen transport by blood and oxygen storage in muscles. To maintain the necessary levels, human iron metabolism requires a minimum of iron in the diet. Iron is also the metal at the active site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants and animals.
== Routine biochemistry analysers == These are machines that process a large portion of the samples going into a hospital or private medical laboratory. Automation of the testing process has reduced testing time for many analytes from days to minutes. The history of discrete sample analysis for the clinical laboratory began with the introduction of the "Robot Chemist" invented by Hans Baruch and introduced commercially in 1959. The AutoAnalyzer is an early example of an automated chemistry analyser using a special flow technique named "continuous flow analysis (CFA)", invented in 1957 by Leonard Skeggs, PhD and first made by the Technicon Corporation. The first applications were for clinical (medical) analysis. The AutoAnalyzer profoundly changed the character of the chemical testing laboratory by allowing significant increases in the numbers of samples that could be processed. Samples used in the analyser include, but are not limited to, blood, serum, plasma, urine, cerebrospinal fluid, and other fluids from within the body. The design based on separating a continuously flowing stream with air bubbles largely reduced slow, clumsy, and error-prone manual methods of analysis. The types of tests include enzyme levels (such as many of the liver function tests), ion levels (e.g. sodium and potassium, and other tell-tale chemicals (such as glucose, serum albumin, or creatinine). Simple ions are often measured with ion selective electrodes, which let one type of ion through, and measure voltage differences.
Sources: en.wikipedia.org
Kiwis and shorebirds with long bills probe for invertebrates; shorebirds' varied bill lengths and feeding methods result in the separation of ecological niches. Divers, diving ducks, penguins and auks pursue their prey underwater, using their wings or feet for propulsion, while aerial predators such as sulids, kingfishers and terns plunge dive after their prey. Flamingos, three species of prion, and some ducks are filter feeders. Geese and dabbling ducks are primarily grazers. Some species, including frigatebirds, gulls, and skuas, engage in kleptoparasitism, stealing food items from other birds. Kleptoparasitism is thought to be a supplement to food obtained by hunting, rather than a significant part of any species' diet; a study of great frigatebirds stealing from masked boobies estimated that the frigatebirds stole at most 40% of their food and on average stole only 5%. Other birds are scavengers; some of these, like vultures, are specialised carrion eaters, while others, like gulls, corvids, or other birds of prey, are opportunists.
== Selected publications == Bolisetty, S.; Peydayesh, M.; Mezzenga, R. (2019). “Sustainable technologies for water purification from heavy metals: review and analysis.” Chemical Society Reviews 48 (2): 463–487. Wei, G.; Su, Z.; Reynolds, N. P.; Arosio, P.; Hamley, I. W.; Gazit, E.; Mezzenga, R. (2017). “Self-assembling peptide and protein amyloids: from structure to tailored function in nanotechnology.” Chemical Society Reviews 46 (15): 4661–4708. Mezzenga, R.; Schurtenberger, P.; Burbidge, A.; Michel, M. (2005). “Understanding foods as soft materials.” Nature Materials 4 (10): 729–740. Nasrabadi, M. N.; Doost, A. S.; Mezzenga, R. (2021). “Modification approaches of plant-based proteins to improve their techno-functionality and use in food products.” Food Hydrocolloids 118: 106789. Adamcik, J.; Jung, J. M.; Flakowski, J.; De Los Rios, P.; Dietler, G.; Mezzenga, R. (2010). “Understanding amyloid aggregation by statistical analysis of atomic force microscopy images.” Nature Nanotechnology 5 (6): 423–428. Bolisetty, S.; Mezzenga, R. (2016). “Amyloid–carbon hybrid membranes for universal water purification.” Nature Nanotechnology 11 (4): 365–371. Cao, Y.; Mezzenga, R. (2019). “Food protein amyloid fibrils: origin, structure, formation, characterization, applications and health implications.” Advances in Colloid and Interface Science 269: 334–356. I. Usov, G. Nyström, J. Adamcik, S. Handschin, C. Schütz, A. Fall, L. Bergström & R. Mezzenga (2015). Understanding nanocellulose chirality and structure–properties relationship at the single fibril level.
=== Surgery === Surgical removal of the pituitary tumor is usually effective in lowering growth hormone levels. Two surgical procedures are available for use. The first is endonasal transsphenoidal surgery, which involves the surgeon reaching the pituitary through an incision in the nasal cavity wall. The wall is reached by passing through the nostrils with microsurgical instruments. The second method is transsphenoidal surgery during which an incision is made into the gum beneath the upper lip. Further incisions are made to cut through the septum to reach the nasal cavity, where the pituitary is located. Endonasal transsphenoidal surgery is a less invasive procedure with a shorter recovery time than the older method of transsphenoidal surgery, and the likelihood of removing the entire tumor is greater with reduced side effects. Consequently, endonasal transsphenoidal surgery is the more common surgical choice. These procedures normally relieve the pressure on the surrounding brain regions and lead to a lowering of GH levels. Surgery is most successful in people with blood GH levels below 40 ng/ml before the operation and with pituitary tumors no larger than 10 mm in diameter. Success depends on the skill and experience of the surgeon. The success rate also depends on what level of GH is defined as a cure. The best measure of surgical success is the normalization of GH and IGF-1 levels. Ideally, GH should be less than 2 ng/ml after an oral glucose load.
Labour was determined to destroy the Liberals and become the sole party of the left. Ramsay MacDonald was forced into a snap election in 1924 and although his government was defeated, he achieved his objective of virtually wiping the Liberals out as many more radical voters now moved to Labour whilst moderate middle-class Liberal voters concerned about socialism moved to the Conservatives. The Liberals were reduced to a mere forty seats in Parliament, only seven of which had been won against candidates from both parties and none of these formed a coherent area of Liberal survival. The party seemed finished, and during this period some Liberals, such as Churchill, went over to the Conservatives while others went over to Labour. Several Labour ministers of later generations, such as Michael Foot and Tony Benn, were the sons of Liberal MPs. Asquith finally resigned as Liberal leader in 1926 (he died in 1928). Lloyd George, now party leader, began a drive to produce coherent policies on many key issues of the day. In the 1929 general election, he made a final bid to return the Liberals to the political mainstream, with an ambitious programme of state stimulation of the economy called We Can Conquer Unemployment!, largely written for him by the Liberal economist John Maynard Keynes. The Liberal Party stood in Northern Ireland for the first and only time in the 1929 general election, gaining 17% of the vote, but won no seats. Nationally the Liberals gained ground, but once again it was at the Conservatives' expense whilst also losing seats to Labour.
== Structure == Selenocysteine has the same structure as cysteine, but with an atom of selenium taking the place of the usual sulfur; it has a selenol group. Like other natural proteinogenic amino acids, cysteine and selenocysteine have L chirality in the older D/L notation based on homology to D- and L-glyceraldehyde. In the newer R/S system of designating chirality, based on the atomic numbers of atoms near the asymmetric carbon, they have R chirality, because of the presence of sulfur or selenium as a second neighbor to the asymmetric carbon. The remaining chiral amino acids, having only lighter atoms in that position, have S chirality.) Proteins which contain a selenocysteine residue are called selenoproteins. Most selenoproteins contain a single selenocysteine residue. Selenoproteins that exhibit catalytic activity are called selenoenzymes.
Sources: en.wikipedia.org
It is rare to find less than five interacting parallel strands in a motif, suggesting that a smaller number of strands may be unstable, however it is also fundamentally more difficult for parallel β-sheets to form because strands with N and C termini aligned necessarily must be very distant in sequence . There is also evidence that parallel β-sheet may be more stable since small amyloidogenic sequences appear to generally aggregate into β-sheet fibrils composed of primarily parallel β-sheet strands, where one would expect anti-parallel fibrils if anti-parallel were more stable. In parallel β-sheet structure, if two atoms Cαi and Cαj are adjacent in two hydrogen-bonded β-strands, then they do not hydrogen bond to each other; rather, one residue forms hydrogen bonds to the residues that flank the other (but not vice versa). For example, residue i may form hydrogen bonds to residues j − 1 and j + 1; this is known as a wide pair of hydrogen bonds. By contrast, residue j may hydrogen-bond to different residues altogether, or to none at all. The hydrogen bond arrangement in parallel beta sheet resembles that in an amide ring motif with 11 atoms. Finally, an individual strand may exhibit a mixed bonding pattern, with a parallel strand on one side and an antiparallel strand on the other.
During his first year in the House, Sanders often alienated allies and colleagues with his criticism of both political parties as working primarily on behalf of the wealthy. In 1991, he co-founded the Congressional Progressive Caucus, a group of mostly liberal Democrats that he chaired for its first eight years, while still refusing to join the Democratic Party or caucus. In 2005, Rolling Stone called Sanders the "amendment king" for his ability to get more roll call amendments passed than any other congressman during the period since 1995, when Congress was entirely under Republican control. Being an independent allowed him to form coalitions across party lines.
==== Light ==== ((N,N'-dimethylacrylamide)-co-4-phenylazophenyl acrylate) at the active site of endoglycanase creates a photoswitchable protein hybrid. The resulting hybrid catalyzes the hydrolysis of glycoside when irradiated by 350 nm UV light, but turns inactive under 420 nm visible light depending on the conformation of the conjugated polymer.
=== Hysteresis === The cloud points upon cooling and heating of a thermoresponsive polymer solution do not coincide because the process of equilibration takes time. The temperature interval between the cloud points upon cooling and heating is called hysteresis. The cloud points are dependent on the cooling and heating rates, and hysteresis decreases with lower rates. There are indications that hysteresis is influenced by the temperature, viscosity, glass transition temperature and the ability to form additional intra- and inter-molecular hydrogen bonds in the phase separated state.
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.
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.