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.
Updated 2026-04-15. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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。
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。
| 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 |
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
For example, the dioxide (FlO2) is expected to be highly unstable to decomposition into its constituent elements (and would not be formed by direct reaction of flerovium with oxygen), and flerovane (FlH4), which should have Fl–H bond lengths of 1.787 Å and would be the heaviest homologue of methane (the lighter compounds include silane, germane and stannane), is predicted to be more thermodynamically unstable than plumbane, spontaneously decomposing to flerovium(II) hydride (FlH2) and H2. The tetrafluoride FlF4 would have bonding mostly due to sd hybridizations rather than sp3 hybridizations, and its decomposition to the difluoride and fluorine gas would be exothermic. The other tetrahalides (for example, FlCl4 is destabilized by about 400 kJ/mol) decompose similarly. The corresponding polyfluoride anion FlF2−6 should be unstable to hydrolysis in aqueous solution, and flerovium(II) polyhalide anions such as FlBr−3 and FlI−3 are predicted to form preferentially in solutions. The sd hybridizations were suggested in early calculations, as flerovium's 7s and 6d electrons share about the same energy, which would allow a volatile hexafluoride to form, but later calculations do not confirm this possibility. In general, spin–orbit contraction of the 7p1/2 orbital should lead to smaller bond lengths and larger bond angles: this has been theoretically confirmed in FlH2. Still, even FlH2 should be relativistically destabilized by 2.6 eV to below Fl+H2; the large spin–orbit effects also break down the usual singlet–triplet divide in the group 14 dihydrides.
Acarbose – Precose or Glucobay Miglitol – Glyset Voglibose Even though the drugs have a similar mechanism of action, there are subtle differences between acarbose and miglitol. Acarbose is an oligosaccharide, whereas miglitol resembles a monosaccharide. Miglitol is fairly well absorbed into the bloodstream, as opposed to acarbose. Moreover, acarbose inhibits pancreatic alpha-amylase in addition to alpha-glucosidase, and is degraded by gut bacterial maltogenic alpha-amylase and cyclomaltodextrinase.
=== Unnatural amino acid incorporation === Cell-free systems have also been used to incorporate unnatural amino acids. Shimizu et al. were able to change a stop codon to a sense codon by omitting the RF1 release factor, indicating ability to insert desired amino acids in unnatural situations. This is of use in systems where working inside a cell is problematic, such as the process of amino acid metabolism preventing specific labelling of amino acids that would be useful in multidimensional NMR spectroscopy. Kigawa et al.were able to successfully label amino acids in a cell-free system where amino acid metabolism was no longer present, thus making such systems useful to NMR studies.
Traces of 40K are found in natural sources of potassium, and it is the most common radioisotope in the human body. Potassium ions are vital for the functioning of all living cells. The transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission; potassium deficiency and excess can each result in numerous signs and symptoms, including an abnormal heart rhythm and various electrocardiographic abnormalities. Fresh fruits and vegetables are good dietary sources of potassium. The body responds to the influx of dietary potassium by increasing potassium excretion by the kidneys and sequestering potassium in the liver and muscles to avoid changes in serum potassium levels. Most industrial applications of potassium exploit the high solubility of its compounds in water, such as saltwater soap. Heavy crop production rapidly depletes the soil of potassium, and this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production.
Sources: en.wikipedia.org
Dexcom, Inc. is an American multinational healthcare company that develops, manufactures, produces and distributes a line of continuous glucose monitoring (CGM) systems for diabetes management. It operates internationally with global headquarters and R&D center in San Diego, California, U.S., and manufacturing facilities in Mesa, Arizona, U.S.; Batu Kawan, Malaysia; and Athenry, County Galway, Ireland.
== Cosmeses == Certain hair shampoos and ointments visually thicken existing hair, without affecting the growth cycle. There have also been developments in the fashion industry with wig design. The fashion accessory has also been shown to be a source of psychological support for women undergoing chemotherapy, with cancer survivors in one study describing their wig as a "constant companion". Other studies in women have demonstrated a more mixed psychosocial impact of hairpiece use. Specialized tattoos, commonly known as scalp micropigmentation, can mimic the appearance of a short buzzed haircut.
=== Defects === There are two kinds of defects: Equilibrium defects, and Non-Equilibrium defects. Self-assembled structures contain defects. Dislocations caused during the assembling of nanomaterials can majorly affect the final structure and in general defects are never completely avoidable. Current research on defects is focused on controlling defect density.[23] In most cases, the thermodynamic driving force for self-assembly is provided by weak intermolecular interactions and is usually of the same order of magnitude as the entropy term. In order for a self-assembling system to reach the minimum free energy configuration, there has to be enough thermal energy to allow the mass transport of the self-assembling molecules. For defect formation, the free energy of single defect formation is given by:
On July 2, 1992, John Crosbie, Canadian Federal Minister of Fisheries and Oceans, declared a two-year moratorium on the Northern Cod fishery, a designated fishing region off the coast of Newfoundland, after data showed that the total cod biomass had suffered a collapse to less than 1% of its normal value. The minister championed the measure as a temporary solution, allowing the cod population time to recover. The fisheries had long shaped the lives and communities on Canada's Atlantic eastern coast for the preceding five centuries. Societies which are dependent on fishing have a strong mutual relationship with them: the act of fishing changes the ecosystems' balance, which forces the fishery and, in turn, the fishing societies to adapt to new ecological conditions. The near-complete destruction of the Atlantic northwest cod biomass off the shores devastated coastal communities, which had been overexploiting the same cod population for decades. The fishermen along the Atlantic northwest had employed modern fishing technologies, including the ecologically devastating practice of trawling, especially in the years leading up to the 1990s, in the misguided belief that fishing stocks are perpetually plentiful and unable to be depleted. After this assumption was empirically and abruptly shown to be incorrect, to the dismay of government officials and rural workers, some 19,000 fishermen and cod processing plant workers in Newfoundland lost their employment.
Half-Life: C.A.G.E.D. (also stylized as Half-Life: Caged) is a game modification of Half-Life by Cayle George and Future Games Select released on September 21, 2017. Made using the GoldSrc engine, the mod includes a single-player campaign in which the player must escape from a closely guarded prison. The mod was released on Microsoft Windows via Steam and was made available on macOS and Linux in December 2017.
Sources: en.wikipedia.org
AtPEPs have been shown to affect resistance against oomycetes and may allow A. thaliana to distinguish between different pathogens. In Nicotiana attenuata, some of the peptides have stopped being involved in defensive roles and instead affect flower morphology.
Under the Nobel Foundation statutes, Hahn had six months to deliver the Nobel Prize lecture, and until 1 October 1946 to cash the 150,000 Swedish krona cheque. Hahn was repatriated from Farm Hall on 3 January 1946, but it soon became apparent that difficulties obtaining permission to travel from the British government meant that he would be unable to travel to Sweden before December 1946. Accordingly, the Academy of Sciences and the Nobel Foundation obtained an extension from the Swedish government. Hahn attended the year after he was awarded the prize. On 10 December 1946, the anniversary of the death of Alfred Nobel, King Gustav V of Sweden presented him with his Nobel Prize medal and diploma. Hahn gave 10,000 krona of his prize to Strassmann, who refused to use it.
Petrus Mailo (27 December 1902 – 12 September 1971) was a Micronesian chief and politician. He served as chief and mayor of Moen from 1944 and was a member of both the Truk Congress and the House of Representatives of the Trust Territory of the Pacific Islands.
==== Dairy products ==== Casokinins and lactokinins, breakdown products of casein and whey, occur naturally after ingestion of milk products, especially cultured milk. Their role in blood pressure control is uncertain. The lactotripeptides Val-Pro-Pro and Ile-Pro-Pro produced by the probiotic Lactobacillus helveticus or derived from casein have been shown to have ACE-inhibiting and antihypertensive functions. In one study, L. helveticus PR4 was isolated from Italian cheeses.
== Contraindications == Contraindications of spironolactone include hyperkalemia (high potassium levels), severe and end-stage kidney disease (due to high hyperkalemia risk, except possibly in those on dialysis), Addison's disease (adrenal insufficiency and low aldosterone levels), and concomitant use of eplerenone. It should also be used with caution in people with certain neurological disorders, as well as those who experience or have experienced anuria (lack of urine production), acute kidney injury, or significant impairment of kidney excretory function with risk of hyperkalemia.
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.
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。