This is a working overview of ACTH fragment, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-15 and is reviewed periodically as new material appears.
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
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. 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.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
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.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
Plastocyanin is one of the family of blue copper proteins that are involved in electron transfer reactions. The copper-binding site is described as distorted trigonal pyramidal. The trigonal plane of the pyramidal base is composed of two nitrogen atoms (N1 and N2) from separate histidines and a sulfur (S1) from a cysteine. Sulfur (S2) from an axial methionine forms the apex. The distortion occurs in the bond lengths between the copper and sulfur ligands. The Cu−S1 contact is shorter (207 pm) than Cu−S2 (282 pm). The elongated Cu−S2 bonding destabilizes the Cu(II) form and increases the redox potential of the protein. The blue color (597 nm peak absorption) is due to the Cu−S1 bond where S(pπ) to Cu(dx2−y2) charge transfer occurs. In the reduced form of plastocyanin, His-87 will become protonated with a pKa of 4.4. Protonation prevents it acting as a ligand and the copper site geometry becomes trigonal planar.
==== Two strategies for searching for intelligent signals ==== Kardashev then analyzed various models and hypotheses of the evolution of civilization. Answering the question of the Russian astronomer Iosif Shklovsky, who in an article published in 1977 entitled Possibility of the Intelligent Life in the Universe Being Unique found it strange that the "shock wave of intelligence" of a supercivilization had not yet reached the limits of the whole Universe, Kardashev put forward two explanatory hypotheses. In the first, he postulated that it would not be useful for a supercivilization to expand the space it occupies in order to maintain its activity, and in the second, it is possible that a civilization, instead of dispersing itself in space, would rather continue its activities of information analysis in order to discover new fundamental laws (such as the exploration of the microcosm, or black holes for example). However, such civilization activities require the use of abundant energy. According to the laws of thermodynamics, an important part of this consumed energy must be converted into radiation of a bolometric magnitude approximately equal to that of the radiation background surrounding the source. The spectral distribution of this intensity must be close to that of a black body. This would be a possible way to search for extraterrestrial civilizations. Such energy consumption would also require a large amount of solid matter for stellar engineering activities, which Kardashev called "cosmic miracles".
In April 2018, the city of Cambridge threatened Ayyadurai with daily fines for an alleged zoning code violation if he did not remove a banner on his campaign bus. The banner featured his campaign slogan, "Only a real Indian can defeat a fake Indian", together with a digitally altered image depicting Warren in a Native American headdress, a reference to her claim to be of part Cherokee descent. The city reversed its position the following month and Ayyadurai, in turn, dropped a lawsuit alleging that his free speech rights had been violated. During the campaign, Ayyadurai appeared on a livestream with Matthew Colligan, a white supremacist known for his participation in the 2017 Unite the Right rally. Colligan requested that Ayyadurai bless a small statue of Kek, the green frog that came to prominence as a symbol of the alt-right during the 2016 United States presidential election. Ayyadurai obliged and described Colligan as "one of our greatest supporters". Ayyadurai also sold pins promoting his campaign that featured a brown-skinned variant of the "Groyper", the namesake and mascot for white nationalist group Groypers which Colligan is affiliated with. Ayyadurai also tweeted on one occasion (and separately retweeted another tweet including) the hashtag "#WWG1WGA", a slogan associated with the QAnon conspiracy theory. Ayyadurai ran unsuccessfully for the Republican nomination in the 2020 U.S. Senate election in Massachusetts. By August 2020, Ayyadurai's campaign had spent $1.4 million, including $1.05 million of Ayyadurai's own funds. After Kevin J.
Kidder's television debut was in an episode of Wojeck aired January 16, 1968, billed as "Margaret Kidder". She very shortly afterward adopted the name Margot Kidder, which she used for the rest of her life. She then made her film debut in a 49-minute film titled The Best Damn Fiddler from Calabogie to Kaladar (1968), a drama set in a Canadian logging community, which was produced by the Challenge for Change. Kidder's 1969 appearance in the episode "Does Anybody Here Know Denny?" on the Canadian drama series Corwin earned her a Canadian Film Award for "outstanding new talent." Kidder's first major feature was the 1969 American film Gaily, Gaily, a period comedy starring Beau Bridges, in which she portrayed a prostitute. She subsequently appeared in a number of TV drama series for the CBC, including guest appearances on Adventures in Rainbow Country, and a semi-regular role as a young reporter on McQueen, and as a panelist on Mantrap, which featured discussions centered on a feminist perspective.
Sources: en.wikipedia.org
==== Natural gas ==== Commonly, HIC of natural gas from the same well has a trend of δDmethane < δDethane < δDpropane < δDC4+. This is because most natural gas is thought to be generated by stepwise thermal cracking that is mostly irreversible and thus governed by normal kinetic isotope effects (KIE) that favor light isotopes. The same trend, known as "the normal order", holds for carbon isotopes in natural gas. For example, Angola gas reportedly has a methane δD range of −190‰ to −140‰, an ethane δD of −146‰ to −107‰, a propane δD of −116‰ to −90‰, and a butane δD of −118‰ to −85‰. However, some recent studies show that opposite patterns could also exist, meaning δDmethane > δDethane > δDpropane. This phenomenon is often called 'isotopic reversal' or 'isotopic rollover'. The isotopic order could also be partly reversed, like δDmethane > δDethane < δDpropane or δDmethane < δDethane > δDpropane. Burruss et al. found that in the deepest samples of northern Appalachian basin the hydrogen isotopic order for methane and ethane is reversed. Liu et al., also found partial reversal in oil-related gas from the Tarim Basin. The mechanism causing this reversal is still unknown. Possible explanations include mixing between gases of different maturities and sources, oxidation of methane, etc. Jon Telling et al., synthesized isotopically reversed (in both C and H) low-molecular alkanes using gas-phase radical recombination reactions in electrical discharge experiments, providing another possible mechanism. Methane is the main component of natural gas.
== Mutations == Mutations in genes encoding uniporters lead to dysfunctional transporter proteins being formed. This loss of function in uniporters causes disruption in cellular function which leads to various diseases and disorders.
If the pressure at the outlet is lower than the pressure at the inlet and remains that way in spite of the pumping, then this pressure difference opens both check valves simultaneously and the liquid flows through the pump head uncontrollably from inlet to outlet. This can happen whether the pump is working or not. This situation can be avoided by placing a correctly rated positive pressure differential check valve downstream of the pump. Such a valve will only open if a minimum rated pressure differential across the valve is exceeded, something which most high-pressure metering pumps can easily exceed.
Sources: en.wikipedia.org
Tryptophan N-monooxygenase is a cytochrome P450 protein containing heme, first isolated from Sinapis alba. It uses molecular oxygen for the oxidation and requires a partner cytochrome P450 reductase for functional expression. This uses nicotinamide adenine dinucleotide phosphate. The reaction proceeds via N-hydroxylation to an intermediate which loses carbon dioxide. The product of the reaction is an intermediate in the biosyntheis of the auxin, indole acetic acid, and the phytoalexin, camalexin.
Tirofiban, inhibitor of the glycoprotein IIb/IIIa, used as a cardiovascular drug Maraviroc, inhibitor of the CCR5-gp120 interaction, used as anti-HIV drug. Venetoclax Lifitegrast Sotorasib Adagrasib Experimental inhibitors in drug development include:
Expense must also be duly considered with such assays as they become more frequently applied in very large studies (e.g. potentially involving thousands of samples). While other approaches are also being made commercially available (e.g. iterative mapping of peptides, fluorescent variation of Edman degradation, and nanopores) these (i) remain broadly untested outside the firms involved; (ii) yield largely, if not completely, only proteogenomic data; (iii) are thus, currently at least, quite limited in terms of any capacity for a broad assessment of proteoforms; (iv) are dependent on the quality of the affinity or other (multiple) reagents required which; (v) tends to also increase costs per assay to the consumer. Notably, while promising, nanopore sequencing is (i) still quite early in development; and (ii) remains unproven in terms of throughput and capacity to address the full range of known PTM and adducts. Thus, the capacity for nanopores to quantitatively address the full breadth of a proteome remains untested. Other technical issues such as potential clogging of pores will also need to be addressed with hopefully routine solutions.
The other method involves transesterification of sucrose and fatty acid methyl ester using sodium methoxide as a basic catalyst. The by-product methanol can be removed via distillation to drive the equilibrium to favor sucrose esters.
Sources: en.wikipedia.org
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。