Everything below concerns heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-12-03. Numbers and descriptions here follow the published literature rather than marketing material.
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
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.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
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.
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.
== Bibliography == Antoni Czubiński, Powstanie Wielkopolskie 1918–1919. Geneza-charakter-znaczenie, Poznań 1978 Antoni Czubiński, Rola Powstania Wielkopolskiego w walce narodu polskiego o powstrzymanie niemieckiego >parcia na wschód<, Przegląd Zachodni 1968, nr 5–6 A. Czubiński, Z.Grot, B.Miśkiiewcz, Powstanie Wielkopolskie 1918–1919. Zarys dziejów, Warszawa 1978 K. Dembski, Wielkopolska w początkach II Rzeczypospolitej. Zagadnienia prawno-ustrojowe, Poznań 1972 Roman Dmowski, Polityka polska i odbudowanie państwa 1925 Z. Grot (ed.), Powstanie wielkopolskie 1918–1919, Poznań 1968 Z. Grot, I. Pawłowski, M. Pirko, Wielkopolska w walce o niepodległość 1918–1919. Wojskowe i polityczne aspekty Powstania Wielkopolskiego, Warszawa 1968 P. Hauser, Niemcy wobec sprawy polskiej X 1918–VI 1919, Poznań 1984 K. Kandziora, Działalność POW w Poznaniu. Przyczynek do historii Polskiej Organizacji Wojskowej zaboru pruskiego w latach 1918–1919, Warszawa 1939 S. Kubiak, Niemcy a Wielkopolska 1918–1919, Poznań 1969 Joseph Lamia: Der Aufstand in Posen (The Uprising in Poznan). Berlin 1919 (in German). Materiały Sesji Naukowej z okazji 50-lecia Powstania Wielkopolskiego 1918/1919, Zaszyty Naukowe UAM 1970, Historia t.10 Witold Mazurczak, Anglicy i wybuch powstania wielkopolskiego. Z dziejów genezy brytyjskiej misji płka H.H.Wade'a w Polsce, [in:] Antoni Czubiński (ed.), Polacy i Niemcy. Dziesięć wieków sąsiedztwa, PWN, Warszawa 1987 Janusz Pajewski, Rodział XXII.
Potential graphene applications include lightweight, thin, and flexible electric/photonics circuits, solar cells, and various medical, chemical and industrial processes enhanced or enabled by the use of new graphene materials, and favoured by massive cost decreases in graphene production.
Other polypeptides and proteins such as amylin and the β amyloid peptide do not have a simple consensus sequence and are thought to aggregate through the sequence segments enriched with hydrophobic residues, or residues with high propensity to form β-sheet structure. Among the hydrophobic residues, aromatic amino-acids are found to have the highest amyloidogenic propensity. Cross-polymerization (fibrils of one polypeptide sequence causing other fibrils of another sequence to form) is observed in vitro and possibly in vivo. This phenomenon is important, since it would explain interspecies prion propagation and differential rates of prion propagation, as well as a statistical link between Alzheimer's and type 2 diabetes. In general, the more similar the peptide sequence the more efficient cross-polymerization is, though entirely dissimilar sequences can cross-polymerize and highly similar sequences can even be "blockers" that prevent polymerization.
Sources: en.wikipedia.org
expression vector Also expression construct. A type of vector, usually a plasmid or viral vector, designed specifically for the expression of a transgene insert in a target cell, rather than for some other purpose such as cloning.
The α-helix is the most abundant type of secondary structure in proteins. The α-helix has 3.6 amino acids per turn with an H-bond formed between every fourth residue; the average length is 10 amino acids (3 turns) or 10 Å but varies from 5 to 40 (1.5 to 11 turns). The alignment of the H-bonds creates a dipole moment for the helix with a resulting partial positive charge at the amino end of the helix. Because this region has free NH2 groups, it will interact with negatively charged groups such as phosphates. The most common location of α-helices is at the surface of protein cores, where they provide an interface with the aqueous environment. The inner-facing side of the helix tends to have hydrophobic amino acids and the outer-facing side hydrophilic amino acids. Thus, every third of four amino acids along the chain will tend to be hydrophobic, a pattern that can be quite readily detected. In the leucine zipper motif, a repeating pattern of leucines on the facing sides of two adjacent helices is highly predictive of the motif. A helical-wheel plot can be used to show this repeated pattern. Other α-helices buried in the protein core or in cellular membranes have a higher and more regular distribution of hydrophobic amino acids, and are highly predictive of such structures. Helices exposed on the surface have a lower proportion of hydrophobic amino acids. Amino acid content can be predictive of an α-helical region.
{\displaystyle {\begin{aligned}F_{1}(kr)&={\frac {\mathrm {ber} (kr)\mathrm {ber} (kR)+\mathrm {bei} (kr)\mathrm {bei} (kR)}{\mathrm {ber} ^{2}(kR)+\mathrm {bei} ^{2}(kR)}},\\[6pt]F_{2}(kr)&={\frac {\mathrm {ber} (kr)\mathrm {bei} (kR)-\mathrm {bei} (kr)\mathrm {ber} (kR)}{\mathrm {ber} ^{2}(kR)+\mathrm {bei} ^{2}(kR)}},\end{aligned}}}
Sources: en.wikipedia.org
Mass spectrometry is used to separate and measure distinct isotopes present in a sample. Archaeologists typically employ isotope ratio mass spectrometers or IRMSs, consisting of an inlet system, ion source, mass analyser and multiple ion detectors. The sample is usually introduced into the mass spectrometer as a gas, with oxygen and carbon being introduced as carbon dioxide. Strontium is too unstable to be easily handled in gas form, instead, it is evaporated and ionised in a vacuum. This use of a solid source is referred to as thermal ionisation mass spectrometry or TIMS. More recently, strontium isotopes have been at the centre of discussion and investigation into the use of laser ablation inductively coupled mass spectrometry (ICP-MS), which is also of interest due to its less invasive nature. Electron bombardment ionises the gas, allowing the molecules to be focused into a beam which is then split by mass into smaller beams - forming a "mass spectrum". The relative intensities of the different beams is then measured in the ion collector and relayed as isotope ratios.
There is evidence humans have been processing fish since the early Holocene. For example, fishbones (c. 8140–7550 BP, uncalibrated) at Atlit-Yam, a submerged Neolithic site off Israel, have been analysed. What emerged was a picture of "a pile of fish gutted and processed in a size-dependent manner, and then stored for future consumption or trade. This scenario suggests that technology for fish storage was already available, and that the Atlit-Yam inhabitants could enjoy the economic stability resulting from food storage and trade with mainland sites."
=== Medicated fishfood === Medicated fishfood is a safe and effective method to deliver medication to fish. One advantage is that medicated food does not contaminate the aquatic environment and also, unlike bath treatments, does not negatively affect fish, filtration and algae growth in the aquarium. The parasites will get treated spot on by medicated food, because the fish is ingesting it.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.