This is a working overview of peptide synthesis, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-25. Anything still debated is marked as such rather than presented as settled.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Analog of an ACTH fragment |
| Amino acid length | Seven residues | Met-Glu-His-Phe-Pro-Gly-Pro |
| Origin | Moscow, 1980s | Institute of Molecular Genetics |
| Approved regions | Russia and some neighboring states | Not cleared in Western markets |
| Common trade names | Multiple national brands | Sold as a nasal formulation |
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.
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。
Her initial drawings and continual discoveries contribute to a broader understanding of protein energetics and evolution. Peter Agre, Nobel laureate and fellow Duke professor, said of the Richardsons' work: "Jane and David’s work allowed us to reveal the form of proteins, and from there it was easier to understand their function". The Richardsons' more recent work has diversified beyond classification and crystallography. In the 1980s they stretched into the fields of synthetic biochemistry and computational biology as pioneers in the de novo design of proteins, a reverse engineering approach to make and test theoretical predictions about protein folding. In the 1990s the Richardsons developed the kinemage system of molecular graphics and David Richardson wrote the Mage program to display them on small computers, for the then-new journal Protein Science. Additionally, they developed all-atom contact analysis (see image) to measure "goodness of fit" inside proteins and in interactions with surrounding molecules. The Kinemage website offers interactive exploration of various 3D protein structures through computer displays using their Mage or KiNG graphics programs. Funded by a National Institutes of Health (NIH) grant, the website is often used as a teaching tool. Textbooks and internet sites that have sourced images from Kinemages include Introduction to Protein Structure by Branden & Tooze, Fundamentals of Biochemistry by Viet, Voet & Pratt, Principles of Biochemistry by Horton et al., and the University of Mississippi's Kinemage Authorship Project.
== Delivery == For a Morpholino to be effective, it must be delivered past the cell membrane into the cytosol of a cell. Once in the cytosol, Morpholinos freely diffuse between the cytosol and nucleus, as demonstrated by the nuclear splice-modifying activity of Morpholinos observed after microinjection into the cytosol of cells. Different methods are used for delivery into embryos, into cultured cells or into adult animals. A microinjection apparatus is usually used for delivery into an embryo, with injections most commonly performed at the single-cell or few-cell stage; an alternative method for embryonic delivery is electroporation, which can deliver oligos into tissues of later embryonic stages. Common techniques for delivery into cultured cells include the Endo-Porter peptide (which causes the Morpholino to be released from endosomes), the Special Delivery system (no longer commercially available, used a Morpholino-DNA heteroduplex and an ethoxylated polyethylenimine delivery reagent), electroporation, or scrape loading. Delivery into adult tissues is usually difficult, though there are a few systems allowing useful uptake of unmodified Morpholino oligos (including uptake into muscle cells with Duchenne muscular dystrophy or the vascular endothelial cells stressed during balloon angioplasty). Though they permeate through intercellular spaces in tissues effectively, unconjugated PMOs have limited distribution into the cytosol and nuclear spaces within healthy tissues following IV administration.
As of 2018, the city has been ranked by GaWC as a Gamma-level global city. Turin is home to much of the Italian automotive industry, and is the base for the headquarters of Fiat, Lancia, and Alfa Romeo. The city has a rich culture and history, and is known for its numerous art galleries, restaurants, churches, palaces, opera houses, piazzas, parks, gardens, theatres, libraries, museums and other venues. Turin is well known for its Baroque, Rococo, Neoclassical, and Art Nouveau architecture. Many of Turin's public squares, castles, gardens, and elegant palazzi, such as the Palazzo Madama, were built between the 16th and 18th centuries. A part of the historical centre of Turin was inscribed in the World Heritage List under the name Residences of the Royal House of Savoy. In addition, the city is home to museums, such as the Museo Egizio, and the Mole Antonelliana, the city's architectural symbol, which in turn hosts the National Museum of Cinema. Turin's attractions make it one of the world's top 250 tourist destinations and the tenth-most visited city in Italy in 2008. The city also hosts some of Italy's most important universities, colleges, academies, lycea, and gymnasia, such as the University of Turin, founded in the 15th century, and the Turin Polytechnic. Turin is also famous worldwide for icons such as the Shroud of Turin, the gianduiotto, the automobile brand Fiat, and the association football club Juventus, which competes with its rival Torino in the Derby della Mole, the city's derby.
Sources: en.wikipedia.org
==== Elimination ==== Ramelteon is excreted 84% in urine and 4% in feces. Less than 0.1% of drug is excreted as unchanged ramelteon. Elimination of ramelteon is essentially complete by 96 hours following a single dose. The elimination half-life of ramelteon is 1 to 2.6 hours while the half-life of M-II, the major active metabolite of ramelteon, is 2 to 5 hours. The half-lives of ramelteon and M-II are substantially longer than that of melatonin, which has a half-life in the range of 20 to 45 minutes. Levels of ramelteon and its metabolites are typically at or below the limit of detectability within 24 hours following a dose.
The digital ion trap (DIT) is an quadrupole ion trap driven by digital signals, typically in a rectangular waveform, generated by switching rapidly between discrete DC voltage levels. The digital ion trap has been mainly developed as a mass analyzer.
=== Leak === On September 19, the Half-Life 2 source code was obtained by a German hacker, Axel Gembe, who had infiltrated Valve's internal network months earlier. According to Gembe, he shared it with another person, who leaked the code online in early October. Fans soon compiled a playable version of Half-Life 2, revealing how unfinished it was. The leaks damaged morale at Valve and slowed development. Fans also provided Valve with the details of people involved in the leaks. In March 2004, Gembe contacted Newell, saying he was a fan and had not acted maliciously. Newell worked with the FBI to invite Gembe to a fake job interview, planning to have him arrested in the United States; however, police arrested him in Germany. In November 2006, Gembe was sentenced to two years' probation. Valve implemented new policies to protect against leaks, such as requiring journalists to attend their office to play it before release.
Sources: en.wikipedia.org
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.
It is registered as a medicine in Russia and has been used clinically there for decades. No regulatory agency in Western Europe or North America has approved it for any indication.
Semax corresponds to the four-to-ten fragment of adrenocorticotropic hormone. Because it omits the first three residues, it lacks the adrenal-stimulating action of the full hormone.
Semax is based on the ACTH(4-10) fragment, a seven-amino-acid segment of adrenocorticotropic hormone. The synthetic peptide retains the core sequence while removing regions associated with endocrine activity. This modification is intended to isolate effects on the nervous system.