The short version of synthetic heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Purity assay | RP-HPLC, UV 214 nm | Typical research grade 95 percent or higher |
| Mass confirmation | ESI-MS or MALDI-TOF | Compared with theoretical value |
| Main degradation route | Methionine oxidation | Sulfoxide formation in solution |
| Powder storage | -20 °C, desiccated | Amber vial, minimal headspace |
| Working solution | Sterile water or saline | Prepare fresh; avoid repeated thawing |
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.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
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.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
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.
== Organic chemistry == In organic chemistry 4-methoxyphenol is used as a polymerisation inhibitor (e.g. acrylates or styrene monomers). 4-Methoxyphenol can be produced from p-benzoquinone and methanol via a free radical reaction.
In surgical praxis, after having emplaced the empty breast implants to the implant pockets, the plastic surgeon then filled each device with saline solution, and, because the required insertion-incisions are short and small, the resultant incision-scars will be smaller and shorter than the surgical scars usual to the long incisions required for inserting pre-filled, silicone-gel implants. When compared to the results achieved with a silicone-gel breast implant, the saline implant can yield acceptable results, of increased breast-size, smoother hemisphere-contour, and realistic texture; yet, it is likelier to cause cosmetic problems, such as the rippling and the wrinkling of the breast-envelope skin, accelerated lower breast pole stretch, and technical problems, such as the presence of the implant being noticeable to the eye and to the touch. The occurrence of such cosmetic problems is likelier in the case of the woman with very little breast tissue, and in the case of the woman who requires post-mastectomy breast reconstruction; thus, the silicone-gel implant is the technically superior prosthetic device for breast augmentation, and for breast reconstruction. In the case of the woman with much breast tissue, for whom sub-muscular emplacement is the recommended surgical approach, saline breast implants can produce an aesthetic result much like that afforded by silicone breast implants. Ultrasound examination and outcome studies have revealed that saline and silicone breast implants look and feel similar.
The light source is shone into a monochromator, diffracted into a rainbow, and split into two beams. It is then scanned through the sample and the reference solutions. Fractions of the incident wavelengths are transmitted through, or reflected from, the sample and the reference. The resultant light strikes the photodetector device, which compares the relative intensity of the two beams. Electronic circuits convert the relative currents into linear transmission percentages or absorbance or concentration values. In an array spectrophotometer, the sequence is as follows:
Certain aspects of the instrumentation (such as detection) are necessarily more complex than for a single-capillary system, but the fundamental principles of design and operation are similar to those shown in Figure 1.
=== Carbon methylation === Radical SAM methylases/methyltransferases are one of the largest yet diverse subgroups and are capable of methylating a broad range of unreactive carbon and phosphorus centers. These enzymes are divided into three classes (Class A, B and C) with representative methylation mechanisms. The shared characteristic is the usage of SAM, split into two distinct roles: one as a source of a methyl group donor, and the second as a source of 5'-dAdo radical. Another class has been proposed (class D) but proved to be wrongly assigned.
Sources: en.wikipedia.org
In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill, or function essentially as normal, via a plastron. Note that despite being internal, the tracheae of arthropods are lined with cuticular tissue and are shed during moulting (ecdysis).
Reporter genes are molecular tools widely used in molecular biology, genetics, and biotechnology to study gene function, expression patterns, and regulatory mechanisms. These genes encode proteins that produce easily detectable signals, such as fluorescence, luminescence, or enzymatic activity, allowing researchers to monitor cellular processes in real-time. Reporter genes are often fused to regulatory sequences of genes of interest, enabling scientists to analyze promoter activity, transcriptional regulation, and signal transduction pathways. Common reporter gene systems include green fluorescent protein (GFP), β-galactosidase (lacZ), luciferase, and chloramphenicol acetyltransferase (CAT), each offering distinct advantages depending on the experimental application. Their versatility makes reporter genes invaluable in fields such as drug discovery, gene therapy, and synthetic biology.
The concept of intracellular colloids as an organizing principle for the compartmentalization of living cells dates back to the end of the 19th century, beginning with William Bate Hardy and Edmund Beecher Wilson who described the cytoplasm (then called 'protoplasm') as a colloid. Around the same time, Thomas Harrison Montgomery Jr. described the morphology of the nucleolus, an organelle within the nucleus, which has subsequently been shown to form through intracellular phase separation. WB Hardy linked formation of biological colloids with phase separation in his study of globulins, stating that: "The globulin is dispersed in the solvent as particles which are the colloid particles and which are so large as to form an internal phase", and further contributed to the basic physical description of oil-water phase separation. Colloidal phase separation as a driving force in cellular organisation appealed strongly to Stephane Leduc, who wrote in his influential 1911 book The Mechanism of Life: "Hence the study of life may be best begun by the study of those physico-chemical phenomena which result from the contact of two different liquids. Biology is thus but a branch of the physico-chemistry of liquids; it includes the study of electrolytic and colloidal solutions, and of the molecular forces brought into play by solution, osmosis, diffusion, cohesion, and crystallization." The primordial soup theory of the origin of life, proposed by Alexander Oparin in Russian in 1924 (published in English in 1936) and by J.B.S.
Signal peptide and prodomain: An N-terminal signal peptide directs cellular secretion of the protein, which is followed by a regulatory prodomain that keeps the protease in a latent state. Fully activating the enzyme requires a two-step proteolytic cleavage of the prodomain by furin (occurring intracellularly after Arg70 and extracellularly after Arg236). Metalloprotease domain: Contains the active site where three histidine residues coordinate a zinc ion (Zn2+). This zinc ion, a bound water molecule, and the catalytic glutamate residue (Glu389) perform peptide bond hydrolysis. Homology modeling suggests that three calcium ions are also coordinated within this domain to stabilize its structure. Ancillary domains: Located C-terminal to the metalloprotease region, these domains are likely essential for substrate recognition and specificity. They consist of a disintegrin-like domain, a cysteine-rich domain, a spacer domain (which forms a β-sandwich fold), and a total of eight thrombospondin (TSP) type 1 repeats. Mucin-like domain: Located towards the C-terminus, this large (415-amino-acid) domain undergoes heavy O-glycosylation and is modified by a chondroitin sulfate chain. The attachment of this glycosaminoglycan chain classifies ADAMTS7 as a proteoglycan, and the chondroitin sulfate chain provides a strong negative charge. PLAC domain: A short, cysteine-rich protease and lacunin (PLAC) domain located at the extreme C-terminus.
American Chemical Society Award in Chromatography and Electrophoresis (1964) with Stanford Moore Richards Medal of the American Chemical Society (1972) with Stanford Moore Kaj Linderstrøm-Lang Award, Copenhagen (1972) with Stanford Moore The Nobel Prize in Chemistry (1972) with Stanford Moore and Christian B. Anfinsen
Sources: en.wikipedia.org
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.
The main chemical risks are methionine oxidation and backbone hydrolysis in solution. Moisture and repeated temperature cycling accelerate both processes. Dry powder held cold and desiccated is considerably more stable than any reconstituted preparation.
It holds a medicine registration in Russia, where it has been used clinically for decades. In most other countries it is treated as a research chemical. That split explains the uneven distribution of clinical literature.
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。