The short version of lyophilized powder fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-06. Anything still debated is marked as such rather than presented as settled.
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.
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.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
== Histological staining == In the clinical setting, amyloid diseases are typically identified by a change in the spectroscopic properties of planar aromatic dyes such as thioflavin T, congo red or NIAD-4. In general, this is attributed to the environmental change, as these dyes intercalate between β-strands to confine their structure. Congo Red positivity remains the gold standard for diagnosis of amyloidosis. In general, binding of Congo Red to amyloid plaques produces a typical apple-green birefringence when viewed under cross-polarized light. Recently, significant enhancement of fluorescence quantum yield of NIAD-4 was exploited to super-resolution fluorescence imaging of amyloid fibrils and oligomers. To avoid nonspecific staining, other histology stains, such as the hematoxylin and eosin stain, are used to quench the dyes' activity in other places such as the nucleus, where the dye might bind. Modern antibody technology and immunohistochemistry has made specific staining easier, but often this can cause trouble because epitopes can be concealed in the amyloid fold; in general, an amyloid protein structure is a different conformation from the one that the antibody recognizes.
During Mahathir's term, Mahathir maintained a collaborative relationship with the West, despite him being an outspoken critic and prioritised development models and collaboration from elsewhere in Asia. On his first day in office, Mahathir announced that his government would prioritise strengthening ties with neighbouring ASEAN countries, particularly through closer economic cooperation. He chose neighbouring Indonesia for his first official overseas visit. Early during his tenure, a small disagreement with the United Kingdom over university tuition fees led to a boycott of all British goods led by Mahathir, in what became known as the "Buy British Last" campaign. Mahathir successfully negotiated with Indonesian President Suharto to bring the 27-year Ligitan and Sipadan dispute with Indonesia to the International Court of Justice for resolution. In a shift from his predecessors, Mahathir frequently condemned Israel and ensured Malaysian support for the Palestine Liberation Organization, although he toned down his criticisms after the Oslo Accords were agreed. He has been internationally acclaimed as the voice of the developing world. As prime minister, Mahathir undertook numerous international visits to enhance diplomatic relations, promote trade, and gather insights on foreign nations. In 1987, he was elected as the president of the International Conference on Drug Abuse and Illicit Trafficking.
== Media impact == Real-life crime scene investigators and forensic scientists warn that popular television shows do not give a realistic picture of the work, often wildly distorting its nature, and exaggerating the ease, speed, effectiveness, drama, glamour, influence and comfort level of their jobs—which they describe as far more mundane, tedious and boring. Some claim these modern TV shows have changed individuals' expectations of forensic science, sometimes unrealistically—an influence termed the "CSI effect". Further, research has suggested that public misperceptions about criminal forensics can create, in the mind of a juror, unrealistic expectations of forensic evidence—which they expect to see before convicting—implicitly biasing the juror towards the defendant. Citing the "CSI effect", at least one researcher has suggested screening jurors for their level of influence from such TV programs. Further, research has shown that newspaper media has been found to shape readers general knowledge and perceptions of science and technology in a rather positive way. It could lead to support of it due to the interest readers may obtain and seek further knowledge on the topic.
A feature film adaptation was announced by Fox 2000 in 2013 with Karen Rosenfelt attached, but went unproduced. Netflix announced a TV adaptation in 2020, to be helmed by Joe Barton, which was released on 28 October 2022 as The Bastard Son & The Devil Himself.
Sources: en.wikipedia.org
Early research in the 19th and 20th centuries on osmosis and diffusion provided the foundation for understanding the passive movement of molecules across cell membranes. In 1855, the physiologist Adolf Fick was the first to define osmosis and simple diffusion as the tendency for solutes to move from a region of higher concentration to a lower concentration, also very well-known as Fick's Laws of Diffusion. Through the work of Charles Overton in the 1890s, the concept that the biological membrane is semipermeable became important to understanding the regulation of substances in and out of the cells. The discovery of facilitated diffusion by Wittenberg and Scholander suggested that proteins in the cell membrane aid in the transport of molecules. In the 1960s - 1970s, studies on the transport of glucose and other nutrients highlighted the specificity and selectivity of membrane transport proteins. Technological advancements in biochemistry helped isolate and characterize these proteins from cell membranes. Genetic studies on bacteria and yeast identified genes responsible for encoding transporters. This led to the discovery of glucose transporters (GLUT proteins), with GLUT1 being the first to be characterized. Identification of gene families encoding various transporters, such as solute carrier (SLC) families, also advanced knowledge on uniporters and its functions. Newer research is focusing on techniques using recombinant DNA technology, electrophysiology and advanced imaging to understand uniporter functions.
The British government of William Ewart Gladstone was unwilling to become mired in a distant war, requiring substantial troop reinforcement and expense, for what was perceived at the time to be a minimal return. An armistice ended the war, and subsequently a peace treaty was signed with the Transvaal President Paul Kruger.
=== Pre-structured motifs === Unlike globular proteins, IDPs do not have spatially-disposed active pockets. 80% of target-unbound IDPs (~4 dozens) subjected to detailed structural characterization by NMR possess linear motifs termed PresMos (pre-structured motifs) that are transient secondary structural elements primed for target recognition. In several cases it has been demonstrated that these transient structures become full and stable secondary structures, e.g., helices, upon target binding. Hence, PresMos are the putative active sites in IDPs.
No significant changes in HbA1c were observed in the control group (Group B) between baseline (7.1%) and the end of the control lessons (7.0%). The number of 'hypos' decreased significantly from 31 to 14 in Group A (p = 0.03) after AIDA lessons, but did not change significantly in Group B from baseline (n = 20) to after the control lessons (n = 22). Full details of the study and the results can be found in the medical / diabetes literature. The study authors concluded that "larger trials involving more patients in more centres are clearly needed, but this proof-of-concept (pilot) study does demonstrate the feasibility of using a prospective randomised controlled trial approach for the evaluation of educational diabetes simulation software such as AIDA".
The two substrates of this enzyme are L-arabinose and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are L-arabino-1,4-lactone, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is L-arabinose:NAD+ 1-oxidoreductase. This enzyme participates in ascorbate and aldarate metabolism.
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.