heptapeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-10-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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。
| 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 |
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
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.
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.
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.
In much of the British Empire, slavery was subject to abolition in 1833, throughout the United States it was abolished in 1865 as a result of the Civil War, which was fought after the attempted secession of the South in order to protect its "Peculiar Institution" (i.e. slavery). In Cuba slavery was abolished in 1886. The last country in the Americas to abolish slavery was Brazil, in 1888. Chattel slavery survived longest in the Middle East. After the trans-Atlantic slave trade had been suppressed, the ancient trans-Saharan slave trade, the Indian Ocean slave trade and the Red Sea slave trade continued to traffic slaves from the African continent to the Middle East. During the 20th century, the issue of chattel slavery was addressed and investigated globally by international bodies created by the League of Nations and the United Nations (UN), such as the Temporary Slavery Commission in 1924–1926, the Committee of Experts on Slavery in 1932, and the Advisory Committee of Experts on Slavery in 1934–1939. By the time of the UN Ad Hoc Committee on Slavery in 1950–1951, legal chattel slavery still existed only in the Arabian Peninsula: in Oman, in Qatar, in Saudi Arabia, in the Trucial States and in Yemen. Legal chattel slavery was finally abolished in the Arabian Peninsula in the 1960s: Saudi Arabia and Yemen in 1962, in Dubai in 1963, and Oman as the last in 1970. The last country to abolish slavery, Mauritania, did so in 1981.
== Documentaries == To Mars by A-Bomb: The Secret History of Project Orion The Oakes Atomic Dream 2001: The Science of Futures Past Cool It Nuclear Dynamite Gaia Symphony III The Starship and the Canoe The Day After Trinity The Untold History of the United States The Uncertainty Has Settled A Glorious Accident Freeman Dyson: Space Dreamer
===== MeSH D08.811.682.830 – succinate cytochrome c oxidoreductase ===== MeSH D08.811.682.830.249 – electron transport complex ii MeSH D08.811.682.830.249.500 – succinate dehydrogenase MeSH D08.811.682.830.500 – electron transport complex iii
When Charles arrives in London as a prospective client, Yasmin uncovers that his finances are collapsing due to NDA settlements with former mistresses, including her childhood nanny. Yasmin confronts him over his predatory behavior, leading to Charles cutting her off financially. In series 3, Yasmin confronts Charles aboard his yacht in Mallorca after catching him having sex with an employee; after a vicious argument, he jumps overboard and drowns while she makes no attempt to save him, with Harper helping cover up her involvement. Back in London, Yasmin is hounded by press amid revelations of Charles’ embezzlement and subsequent disappearance. Working on the merged CPS/FX desk, she helps rescue the spiraling Lumi IPO and begins a relationship with CEO Henry Muck, which she ends after learning of his harassment of employees. After rejecting Eric’s advances and being betrayed by Harper in a short against Pierpoint, Yasmin is fired following the leak of images of her father’s corpse. During a visit to Henry’s estate, Yasmin and Robert finally have sex and confess their love, but Yasmin ultimately agrees to marry Henry for protection and security. Months on, Yasmin’s public image has recovered, and she and Harper have reconciled. In series 4, Yasmin reinvents herself as a socialite and political power broker as her marriage to Henry deteriorates following his loss of his parliamentary seat. She secures Henry the CEO role at fintech firm Tender and builds ties with Labour MP Jennifer Bevan to aid the company’s regulatory ambitions.
Sources: en.wikipedia.org
Since then the community has treated the ordinary fungal binomial as the correct name, whether the fungus is lichenised in nature or grown axenically in culture. While most authors still relied on a stand‑alone lichen framework, a few pioneers argued that lichens should be incorporated into the wider fungal system. John Axel Nannfeldt opened the door in 1932 by dividing the Ascomycota into "ascohymenial" and "ascolocular" lineages based on ascoma development and ascus wall structure, a paradigm that implicitly scattered lichen‑forming fungi across several ordinary ascomycete orders. Rolf Santesson took the first practical step in 1952: studying foliicolous (leaf-dwelling) lichens, he slotted them into Nannfeldt's ascomycete orders rather than the catch-all "Lichenes". Each genus went into an ordinary ascomycete order or family alongside non-lichenised fungi. Each genus thus sat alongside non‑lichenised relatives, showing that lichens required no special Linnaean compartment. This idea was bold for its time (challenging the status quo). Even by the mid-20th century, most lichen funga still treated "Lichenes" as a separate category — lichen specialists maintained their own journals, herbaria, and methods. True integration with mainstream fungal classification only gathered pace once modern molecular methods arrived. Even after it was superseded, Zahlbruckner's catalogue—tens of thousands of names—remained the baseline for later revisions. Within that framework, lichenologists were already aware of potential flaws.
== References == Carlsson, J.; Forssell Aronsson, E; Hietala, SO; Stigbrand, T; Tennvall, J; et al. (2003). "Tumour therapy with radionuclides: assessment of progress and problems". Radiotherapy and Oncology. 66 (2): 107–117. doi:10.1016/S0167-8140(02)00374-2. PMID 12648782. "Radioisotopes in Industry". World Nuclear Association. Archived from the original on 27 February 2013. Retrieved 2 May 2008. Martin, James (2006). Physics for Radiation Protection: A Handbook. John Wiley & Sons. p. 130. ISBN 978-3527406111.
In December 2019, the US Food and Drug Administration (FDA) announced that it learned that some metformin medicines manufactured outside the United States might contain a nitrosamine impurity called N-nitrosodimethylamine (NDMA), classified as a probable human carcinogen, at low levels. Health Canada announced that it was assessing NDMA levels in metformin. The European Medicines Agency provided an update on NDMA in metformin. In February 2020, the FDA found NDMA levels in some tested metformin samples that did not exceed the acceptable daily intake. In February 2020, Health Canada announced a recall of Apotex immediate-release metformin, followed in March by recalls of Ranbaxy metformin and in March by Jamp metformin. In May 2020, the FDA asked five companies to voluntarily recall their sustained-release metformin products. The five companies were not named, but they were revealed to be Amneal Pharmaceuticals, Actavis Pharma, Apotex Corp, Lupin Pharma, and Marksans Pharma Limited in a letter sent to Valisure, the pharmacy that had first alerted the FDA to this contaminant in metformin via a Citizen Petition. In June 2020, the FDA posted its laboratory results showing NDMA amounts in metformin products it tested. It found NDMA in certain lots of ER metformin and is recommending companies recall lots with levels of NDMA above the acceptable intake limit of 96 nanograms per day. The FDA is also collaborating with international regulators to share testing results for metformin.
=== Post 1930s === The field of fermentation has been critical to producing a wide range of consumer goods, from food and drink to industrial chemicals and pharmaceuticals. Since its early beginnings in ancient civilizations, fermentation has continued to evolve and expand, with new techniques and technologies driving advances in product quality, yield, and efficiency. The period from the 1930s onward saw a number of significant advancements in fermentation technology, including the development of new processes for producing high-value products like antibiotics and enzymes, the increasing importance of fermentation in the production of bulk chemicals, and a growing interest in the use of fermentation for the production of functional foods and nutraceuticals. In the 1970s and 1980s, fermentation became increasingly important in producing bulk chemicals like ethanol, lactic acid, and citric acid. This led to developing new fermentation techniques and genetically engineered microorganisms to improve yields and reduce production costs. In the 1990s and 2000s, there was a growing interest in fermentation to produce functional foods and nutraceuticals, which have potential health benefits beyond basic nutrition. This led to new fermentation processes, probiotics, and other functional ingredients.
A chemical system is said to be in equilibrium when the quantities of the chemical entities involved do not and cannot change in time without the application of an external influence. In this sense a system in chemical equilibrium is in a stable state. The system at chemical equilibrium will be at a constant temperature, pressure or volume and a composition. It will be insulated from exchange of heat with the surroundings, that is, it is a closed system. A change of temperature, pressure (or volume) constitutes an external influence and the equilibrium quantities will change as a result of such a change. If there is a possibility that the composition might change, but the rate of change is negligibly slow, the system is said to be in a metastable state. The equation of chemical equilibrium can be expressed symbolically as
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.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。