This is a working overview of 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.
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.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | ≥ 95 % of peak area by HPLC | Some suppliers quote 98 % or higher |
| Identity confirmation | Mass spectrometry (electrospray or MALDI) | Observed mass is compared with the calculated mass |
| Common analytical method | Reversed-phase HPLC on a C18 column | Acetonitrile and water gradients with trifluoroacetic acid |
| Primary degradation route | Oxidation of the methionine residue | Yields a sulfoxide that separates cleanly on chromatography |
| Storage of dissolved material | Aliquoted and frozen at −20 °C or below | Single-use aliquots avoid repeated temperature cycling |
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
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.
The Chinese People's Armed Police Coast Guard Bureau, also abbreviated as China Coast Guard is the agency for maritime search and rescue and law enforcement in the territorial waters of the People's Republic of China. The China Coast Guard was formerly the maritime branch of the People's Armed Police (PAP) Border Security Force under the Ministry of Public Security until 2013. In March 2013, China announced it would form a unified Coast Guard commanded by the State Oceanic Administration. This renewed Coast Guard has been in operation since July 2013. As of 1 July 2018, the China Coast Guard was transferred from civilian control of the State Council and the State Oceanic Administration, to the People's Armed Police, ultimately placing it under the command of the Central Military Commission (CMC). According to Joel Wuthnow of the Institute for National Strategic Studies, the Coast Guard Command within the People's Armed Police possibly is of Corps Leader Grade, led by a Commandant who usually holds the rank of major general. In June 2018, China Coast Guard was granted maritime rights and law enforcement akin civilian law enforcement agencies in order to carry out contrast of illegal activities, keep peace and order, as well as safeguarding security at sea, when performing duties related to the use of marine resources, protection of marine environment, regulation of fishery, and anti-smuggling. There are currently 3 regional bureaus:
=== Safety === The International Agency for Research on Cancer (IARC) has categorized TiO2 as an IARC group 2B carcinogen. The IARC made these decisions based on studies where rats are exposed to high concentrations of pigment-grade and ultrafine TiO2 dust. The lung cancers in rats appear similar pathology to those seen in people who are working in a dusty environment, thus the IARC concluded that the same impacts from high concentrations of pigment-grade and ultrafine TiO2 dust are relevant to human health. However, ZnO is generally considered as safe a substance by the FDA when utilized as an UV filter as indicated by beauty care products directives. Although both the US Environmental Protection Agency and the European Community (inside the Registration, Evaluation, Authorization and Restriction of Chemical Substances law) have taken preventative steps to reduce nanoparticle risk, there are still no standardized rule for nanoparticles specifically.
=== Structure === Unlike traditionally prepared food, the variety of food that can be manufactured using 3D printing is limited by the physical characteristics of the materials. Food materials are generally much softer than the weakest plastic used in 3D printing, making the printed structures very fragile. So far, most studies use trial and error as an approach to overcoming this challenge, but scientists are working on developing new methods that are able to predict the behavior of different materials during the printing process. These methods are developed by analyzing the rheological properties of the materials and their relation to the printing stability.
Sources: en.wikipedia.org
Charles David Sherrill is a professor of chemistry and computational science and engineering at Georgia Tech working in the areas of theoretical chemistry, computational quantum chemistry, and scientific computing. His research focuses on the development and application of theoretical methods for non-covalent interactions between molecules. He is the lead principal investigator of the Psi open-source quantum chemistry program.
=== Candidacy for mayor of Porto Alegre in 2020 === In June 2020, Melo launched his pre-candidacy to run for mayor again, bolstered by a unanimous intra-party vote. His vice-mayoral candidate was Ricardo Gomes (DEM). Other members of his coalition included Cidadania, Solidariedade, Christian Democracy, and the PRTB. Despite the PSL, the former party of former president Jair Bolsonaro, officially supporting Marchezan Júnior's reelection campaign, some deputies from the party campaigned for Melo. In the first round, he received 200,280 votes (31%), and advanced to the second round against Manuela d'Ávila, who received 187,262 (29%). Melo received support from Gustavo Paim (PP), Valter Nagelstein (PSD), João Derly (Republicanos), and from the PSDB. Melo was elected in the second round with 370,550 votes, or 54.63% of the vote.
=== Pharmacodynamics === Several in vitro and in vivo studies have demonstrated that dihydroergocriptine is an effective anti-Parkinson drug, most likely exerting its effects as a potent agonist of D2 receptors. The Kd of DHEC is found to be around 5-8 nM at D2 receptors. Less certain is the contribution of its partial D1 receptor and D3 receptor agonist activity. DHEC has a lower affinity for D1 and D3 receptors (Kd is around 30 nM for both) than for D2 receptors. It is widely believed that dopamine receptor agonists demonstrate their antiparkinsonian effects by stimulating D2 receptors primarily, but other dopamine receptors, such as D1 and D3 may be involved. Remarkably, DHEC is said to not significantly interact with serotonergic and adrenergic receptors.
== Bibliography == Kardashian, Kim; Kardashian, Kourtney; Kardashian, Khloé (2010). Kardashian Konfidential. St. Martin's Press. ISBN 978-0-312-62807-9. Kardashian, Kim; Kardashian, Kourtney; Kardashian, Khloé (2011). Dollhouse. William Morrow. ISBN 9780062063847. Kardashian, Khloe (2015). Strong Looks Better Naked. Regan Arts. ISBN 9781682450772.
Sources: en.wikipedia.org
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.
The methionine residue at the start of the chain is vulnerable to oxidation, producing a sulfoxide variant. Amide bonds can also hydrolyze, though more slowly under neutral conditions. Cold storage, oxygen exclusion and minimization of freeze-thaw cycles slow both processes but do not stop them.
A purity number on a certificate does not establish that a powder is the same product as a registered nasal medicine. Counter-ion content, residual solvents and peptide-related impurities may differ between the two. Independent verification is the only way to narrow that gap.
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.