If you have been reading about 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.
Updated 2025-10-19. Numbers and descriptions here follow the published literature rather than marketing material.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffers |
| Typical storage temperature | -20 °C | Dry, desiccated, protected from light |
| Typical analytical method | RP-HPLC with UV detection | Often paired with LC-MS |
| Water content | Reported as Karl Fischer value | Freeze-dried material is hygroscopic |
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
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。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
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.
== Research == Antibodies and antigens, produced in the Human Protein Atlas workflow, are used in research projects to study potential biomarkers in various diseases, such as breast cancer, prostate cancer, colon cancer, diabetes, autoimmune diseases, ovarian cancer and renal failure. Researchers involved with Human Protein Atlas projects, are sharing protocols and method details in an open-access group on protocols.io. A large effort is put into validating the antibody reagents used for profiling of tissues and cells, and the HPA has implemented stringent antibody validation criteria as suggested by the International Working Group for Antibody Validation (IWGAV).
An asymptomatic skin disorder of the vulval vestibule is vestibular papillomatosis, which is characterised by fine, pink projections from either the epithelium of the vulva or from the labia minora. Dermatoscopy can distinguish this condition from genital warts. A subtype of psoriasis, an autoimmune disease, is inverse psoriasis in which red patches can appear in the skin folds of the labia.
== Further reading == Godwin, P.; Hancock, I. (1995). Rhodesians Never Die – The Impact of War and Political Change on White Rhodesia. Harare, Zimbabwe: Baobab Books. ISBN 0-908311-82-6. Stiff, P.; Reid-Daly, R. (1982). Selous Scouts: Top Secret War. Alberton, South Africa: Galago. Stapleton, T. (2011). African Police and Soldiers in Colonial Zimbabwe, 1923–80. University Rochester Press. ISBN 978-1580463805. Stapleton, Timothy J. (2011). African Police and Soldiers in Colonial Zimbabwe, 1923–80. Rochester, New York: University of Rochester Press. ISBN 9781580467339. Stapleton, Tim (2015). "'Tracking, tracking and more tracking was their motto': bush tracking and warfare in late twentieth-century Southern Africa". War & Society. 34 (4): 301–323. doi:10.1080/07292473.2015.1128658. S2CID 155302459. White, Luise (November 2004). "Precarious Conditions: A Note on Counter-Insurgency in Africa after 1945". Gender & History. 16 (3): 603–625. doi:10.1111/j.0953-5233.2004.00358.x. S2CID 143212408.
Sources: en.wikipedia.org
== Ductal cell physiology == While ductal cells are a minor type of cell in the adult pancreas, they have a critical function besides making the network that transfers enzymes from acini to the digestive tract. The primary function of pancreas ductal cells is to secrete a bicarbonate-rich, isotonic fluid. This fluid washes away the inactive form of digestive enzymes in the ductal system, neutralizes stomach acidity and mucins, and creates a pH environment necessary for the pancreas's normal function. Multiple factors affect the rate of bicarbonate secretion: species, cell location in the ductal system, secretory rate, etc. When stimulated, bicarbonate levels can get to 140mM. Due to this, there is a contrast in concentration between the outside and inside environment of ductal cells. The channels and ion transporters on ductal cells vary on the luminal and basolateral membrane, meaning there is functional polarization of the ductal cell. The largest network branches in this system contain goblet cells that interact with ductal cells, making up about 2% of this structure—these cells aid mucin assembly. Furthermore, unlike other exocrine glands, the pancreas does not have myoepithelial cells around the ducts. Ductal cells have a single cilium that is made up of nine peripheral doublets but does not have a central microtubule. This cilium is considered vital for perceiving flow in ducts.
They demanded that a domestic revolutionary army should be raised and that the price of bread should be fixed at three sous a pound, that nobles holding senior rank in the army should be dismissed, that armouries should be created for arming the sans-culottes, the departments of State purged, suspects arrested, the right to vote provisionally reserved to sans-culottes only, and a fund set apart for the relatives of those defending their country and for the relief of aged and infirm. According to Hampson, the subject is quite extraordinarily complicated and obscure. The next day all Paris was in arms. Hanriot was ordered to march his National Guard, by this time mostly consisting of sans-culottes, from the town hall to the Palais National. On 2 June 1793, a large force of supposedly 80,000 sans-culottes and National Guards led by Hanriot, surrounded the convention with 160–172 guns. On 4 September, the sans-culottes again invaded the convention. They demanded tougher measures against rising prices and the setting up of a system of terror to root out the counter-revolution. The sans-culottes took an especially active interest in the revolutionary army. A "sans-culotte army" (in a sense, Robespierre's brain-child) was formed in Paris.
== Retail products == In 2016, the company began offering a canned version of the Draft Latte, a cold-pressed espresso and frothed milk latte which was available on tap in stores. Draft Lattes were initially available in four flavors. The cans for the latte were designed by CEO Todd Carmichael and produced by Crown Holdings. The can employed a valve mechanism at the base for injection of nitrous oxide. Manufacturing of the cans moved from Pennsylvania to a new facility in Norton Shores, Michigan in 2016. A Nitro cold brew was also in the works around 2015. Other products include Different Drum, a coffee-infused rum, produced at a micro-distillery located in its Fishtown, Philadelphia cafe, and a line of La Colombe single-origin and blended roasted coffees, which are available for purchase in retail stores or via the company's website. The company also produces retail cold brew in larger 42oz bottles. In 2020, the company announced a can of instant coffee with new self-heating technology.
The strategic mission of the SSM-N-8 and the P-5 was taken up by submarine-launched ballistic missile beginning with the US Navy's Polaris missile, and subsequently the Poseidon and Trident missiles. Germany is working on the torpedo tube-launched short-range IDAS missile, which can be used against ASW helicopters, as well as surface ships and coastal targets.
Sources: en.wikipedia.org
=== Nuclear weapons === Neptunium is fissionable, and could theoretically be used as fuel in a fast-neutron reactor or a nuclear weapon, with a critical mass of around 60 kilograms. In 1992, the U.S. Department of Energy declassified the statement that neptunium-237 "can be used for a nuclear explosive device". It is not believed that an actual weapon has ever been constructed using neptunium. As of 2009, the world production of neptunium-237 by commercial power reactors was over 1000 critical masses a year, but to extract the isotope from irradiated fuel elements would be a major industrial undertaking. In September 2002, researchers at the Los Alamos National Laboratory briefly produced the first known nuclear critical mass using a significant fraction of neptunium, in combination with shells of enriched uranium (uranium-235), discovering that the critical mass of a bare sphere of neptunium-237 "ranges from kilogram weights in the high fifties to low sixties", showing that it "is about as good a bomb material as [uranium-235]". The United States Federal government made plans in March 2004 to move America's supply of separated neptunium to a nuclear-waste disposal site in Nevada.
== Society and culture == As of 2018, there is a lack of compelling evidence to conclude superiority of insulin aspart over human insulin in type 2 diabetes. It is thus unclear why the shifting of people from human insulin to insulin aspart has occurred. In type 1 diabetes it appears to result in slightly better blood sugar control.
== Further reading == Görlich D (Jun 1997). "Nuclear protein import". Current Opinion in Cell Biology. 9 (3): 412–9. doi:10.1016/S0955-0674(97)80015-4. hdl:11858/00-001M-0000-002D-1CC5-E. PMID 9159081. Lusk CP, Blobel G, King MC (May 2007). "Highway to the inner nuclear membrane: rules for the road". Nature Reviews Molecular Cell Biology. 8 (5): 414–20. doi:10.1038/nrm2165. PMID 17440484. S2CID 21070484.
=== Tangential trapezoid === If the incircle is tangent to the sides AB and CD at W and Y respectively, then a tangential quadrilateral ABCD is also a trapezoid with parallel sides AB and CD if and only if
=== Classification of cephalosporins === The cephalosporin class is very extensive so a good classification system is necessary to distinguish different cephalosporins from each other. There are few chemical and activity features that could be used for classification, for example chemical structure, side chain properties, pharmacokinetic, spectrum of activity or clinical properties. Despite these variable features the most common classification system for cephalosporins is to divide them into generations. The generation system is based on different antimicrobial activity shown by different cephalosporins.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.
Dry lyophilised powder is generally kept at minus twenty degrees Celsius, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they encourage aggregation and moisture uptake. Solutions are less stable than the solid form and degrade faster at room temperature.
A certificate documents what the supplier measured, not what an independent party confirmed. Methods, instruments and acceptance criteria can differ between suppliers. Third-party testing is the usual way to resolve discrepancies.
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.