If you have been reading about ACTH analog 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.
Last reviewed on 2026-05-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
| 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.
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.
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。
Pa s. This is about a ten thousand times that of water at room temperature, but it is small enough to enable the LAF-1 droplets to flow like a liquid. Generally, interaction strength (affinity) and valence (number of binding sites) of the phase separating biomolecules influence their condensates viscosity, as well as their overall tendency to phase separate.
==== Physiological effects ==== Angiotensin II exhibits endocrine, autocrine/paracrine, and intracrine functions. It promotes aldosterone release from the adrenal cortex, as well as arginine vasopressin release from the posterior pituitary. It acts directly upon the proximal tubules of the kidney to regulate water and Na+ reabsorption, promoting reabsorption at very low concentrations while increasingly inhibiting reabsorption with increasing concentrations. In the proximal tubule, it promotes Na+ reabsorption and H+ excretion (which is coupled to bicarbonate reabsorption) by the Na+/H+ exchanger. It causes venous and arterial vasoconstriction by a Gq alpha subunit-coupled receptor upon vascular smooth muscle cells (with downstream IP3-dependent mechanism causing a rise in intracellular Ca2+ to effect smooth muscle excitation-contraction coupling), thus acting to increase blood pressure.
Partition coefficient log P in −0.4 to +5.6 range Molar refractivity from 40 to 130 Molecular weight from 180 to 480 Number of atoms from 20 to 70 (includes H-bond donors [e.g. OHs and NHs] and H-bond acceptors [e.g. Ns and Os]) Veber's Rule further questions a 500 molecular weight cutoff. The polar surface area and the number of rotatable bonds has been found to better discriminate between compounds that are orally active and those that are not for a large data set of compounds. In particular, compounds which meet only the two criteria of:
Fluorescent proteins with other chromophores, such as UnaG with bilirubin, can display unique properties like red-shifted emission above 600 nm or photoconversion from a green-emitting state to a red-emitting state. They can have excitation and emission wavelengths far enough apart to achieve conversion between red and green light. A new class of fluorescent protein was engineered from α-allophycocyanin, a phycobiliprotein found in the cyanobacterium Trichodesmium erythraeum, and was named small ultra red fluorescent protein (smURFP) in 2016. smURFP autocatalytically incorporates the chromophore biliverdin without the need for an external protein known as a lyase. Jellyfish- and coral-derived GFP-like proteins require oxygen and produce a stoichiometric amount of hydrogen peroxide upon chromophore formation. smURFP does not require oxygen or produce hydrogen peroxide. smURFP has a large extinction coefficient (180,000 M−1 cm−1) and has a modest quantum yield (0.20), which makes it comparable biophysical brightness to eGFP and ~2-fold brighter than most red or far-red fluorescent proteins derived from coral. smURFP spectral properties are similar to the organic dye Cy5.
Sources: en.wikipedia.org
One of the claimants of the English throne opposing William the Conqueror, Edgar Atheling, eventually fled to Scotland. King Malcolm III of Scotland married Edgar's sister Margaret, and came into opposition to William who had already disputed Scotland's southern borders. William invaded Scotland in 1072, riding as far as Abernethy where he met up with his fleet of ships. Malcolm submitted, paid homage to William and surrendered his son Duncan as a hostage, beginning a series of arguments as to whether the Scottish Crown owed allegiance to the King of England. Normans went into Scotland, building castles and founding noble families that would provide some future kings, such as Robert the Bruce, as well as founding a considerable number of the Scottish clans. King David I of Scotland, whose elder brother Alexander I had married Sybilla of Normandy, was instrumental in introducing Normans and Norman culture to Scotland, part of the process some scholars call the "Davidian Revolution". Having spent time at the court of Henry I of England (married to David's sister Maud of Scotland), and needing them to wrestle the kingdom from his nephew Máel Coluim mac Alaxandair, David had to reward many with lands. The process was continued under David's successors, most intensely of all under William the Lion. The Norman-derived feudal system was applied in varying degrees to most of Scotland.
However, as the atrial baroreceptors increase their rate of firing and as they stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase heart rate. The opposite is also true. Chemoreceptors present in the carotid body or adjacent to the aorta in an aortic body respond to the blood's oxygen, carbon dioxide levels. Low oxygen or high carbon dioxide will stimulate firing of the receptors. Exercise and fitness levels, age, body temperature, basal metabolic rate, and even a person's emotional state can all affect the heart rate. High levels of the hormones epinephrine, norepinephrine, and thyroid hormones can increase the heart rate. The levels of electrolytes including calcium, potassium, and sodium can also influence the speed and regularity of the heart rate; low blood oxygen, low blood pressure and dehydration may increase it.
=== Colubrids === Opisthoglyphous colubrids have enlarged, grooved teeth situated at the posterior extremity of the maxilla, where a small posterior portion of the upper labial or salivary gland produces venom.
M + Ph2CO → M+Ph2CO•− Generally sodium is used as the alkali metal. Sodium-benzophenone ketyl is used in the purification of organic solvents, particularly ethers, because it reacts with water and oxygen to give non-volatile products. Adsorbents such as alumina, silica gel, and especially molecular sieves are superior and far safer. The sodium-benzophenone method is common since it gives a visual indication that water, oxygen, and peroxides are absent from the solvent. Large scale purification may be more economical using devices which utilize adsorbents such as the aforementioned alumina or molecular sieves. The ketyl is soluble in the organic solvent being dried, which leads to faster purification. In comparison, sodium is insoluble, and its heterogeneous reaction is much slower. When excess alkali metal is present a second reduction may occur. The twice reduced specie presents as a clear red (extra-dry) solution. A color transformation from deep opaque blue (pure once-reduced benzophenone) to red with stages of opaque purple, indicate a mix of anion and bisanion.
== Plot == In early 2016, one to two months after the events of the "Cold War" operation, The Hong Kong Police Force holds a funeral for two Senior Assistant Commissioners killed previously. Shortly after, Commissioner Sean Lau receives a call from one of the culprits behind the theft of the police van. He is told that his wife has been kidnapped and that he must release Joe Lee for her to survive. Lau overrides standard procedure to transfer Joe out of prison, and is told by the kidnapper to bring Joe to the metro station. There, Joe is able to escape with the aid of several accomplices, one of whom sets off a bomb. The culprits leave Lau's wife alive at their hideout. Lau's actions are criticized by the media and by numerous politicians, leading to a public inquiry. Fearing that the police have been infiltrated, Lau privately requests Billy Cheung, an ICAC Principal Investigator who assisted him previously, to form a separate squad independent of the police in order to track the culprits. Meanwhile, MB Lee, the deputy police commissioner approaching retirement, is confronted by his fugitive son along with Peter Choi, a former police commissioner and Lee's former mentor who is now manipulating politics behind the scenes. Choi is revealed as the mastermind behind the troubles of the EU police van disappearance, and his current goal is to remove Lau, who is not a member of his ring, and to place his own followers into positions of power during the next election.
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.
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.