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 2026-07-03. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
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.
| 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 |
In 2024, Sinclair resigned as the President of The Academy for Health and Lifespan Research, an organization made up of a group of scientists that Sinclair had co-founded. The resignation came after what The Wall Street Journal described as a "cascade" of resignations from outraged members of The Academy after Sinclair and his brother announced that Animal Bioscience had proven that a supplement for dogs with undisclosed ingredients reversed aging. The claim was also met with criticism and skepticism from other longevity researchers.
topoisomerase Any of a class of DNA-binding enzymes which catalyze changes in the topological state of a double-stranded DNA molecule by nicking or cutting the sugar-phosphate backbone of one or both strands, relaxing the torsional stress inherent in the double helix and unwinding or untangling the paired strands before re-ligating the nicks. This process is usually necessary prior to replication and transcription. Topoisomerases thereby convert DNA between its relaxed and supercoiled, linked and unlinked, and knotted and unknotted forms without changing the sequence or overall chemical composition, such that the substrate and product molecules are structural isomers, differing only in their shape and their twisting, linking, and/or writhing numbers.
After Banting's death, Best "claimed that the crucial innovation of using alcohol to remove toxic impurities had largely been his own", even though this had actually been Collip's key contribution. In 1972, an official history of the Nobel Committee declared that omitting Best might have been a mistake. In fact, Best was not considered because he was never nominated. Nomination for a Nobel Prize can only be made by certain individuals, including former recipients of the Prize, and his central role along with Banting was not known to those who had the ability to make nominations. Best was subsequently nominated for the 1950 Nobel Prize in physiology based on his work on choline and heparin. At the Centenary Celebration of the Nobel Prize for the Discovery of Insulin held by the Toronto Medical Society on November 27, 2023, Professor Erling Norrby, former chair of the Nobel Assembly at the Karolinska Institute, made a presentation - The Optimal Nobel Prize for Physiology or Medicine and presented the following information from the Nobel archives: “Best was nominated 14 times 1950-1954. The main nominator was Henry Dale who had been supervisor for Best’s Ph.D. work. The discovery proposed to be awarded was Best’s work on the lipotropic effect of choline, but Dale argued that separately that Best should have shared the 1923 prize to Banting. Best was subject to four evaluations by Ulf von Euler who gave support to Dale’s nomination. Although Best was declared worthy of a prize (1951, 1952, 1954) he never received it.”
By September 1604, Dmitri I had gathered a force of 2,500 men, of whom 1,400 were Cossacks. Two thirds of these "cossacks", however, were in fact Ukrainian civilians, only 500 being professional Ukrainian Cossacks. On July 4, 1610, 4,000 Ukrainian Cossacks fought in the Battle of Klushino, on the side of the Polish-Lithuanian Commonwealth. They helped to defeat a combined Muscovite-Swedish army and facilitate the occupation of Moscow from 1610 to 1611, riding into Moscow with Stanisław Żółkiewski. The final attempt by King Sigismund and Wladyslav to seize the throne of Muscovy was launched on April 6, 1617. Although Wladyslav was the nominal leader, it was Jan Karol Chodkiewicz who commanded the Commonwealth forces. By October, the towns of Dorogobuzh and Vyazma had surrendered. But a defeat, when the counterattack on Moscow by Chodkiewicz failed between Vyasma and Mozhaysk, prompted the Polish-Lithuanian army to retreat. In 1618, Petro Konashevych-Sahaidachny continued his campaign against the Tsardom of Russia on behalf of the Cossacks and the Polish-Lithuanian Commonwealth. Numerous Russian towns were sacked, including Livny and Yelets. In September 1618, with Chodkiewicz, Konashevych-Sahaidachny laid siege to Moscow, but peace was secured.
Sources: en.wikipedia.org
Once across the interface, the tails and loops form whatever bonds are favorable. In the case of polymer-on-polymer surfaces, this means more van der Waals forces. While these may be brittle, they are quite strong when a large network of these bonds is formed. The outermost layer of each surface plays a crucial role in the adhesive properties of such interfaces, as even a tiny amount of interdigitation – as little as one or two tails of 1.25 angstrom length – can increase the van der Waals bonds by an order of magnitude.
In Kashmir, saffron is mostly classified into two main categories called mongra (stigma alone) and lachha (stigmas attached with parts of the style). Countries producing less saffron do not have specialised words for different grades and may only produce one grade. Artisan producers in Europe and New Zealand have offset their higher labour charges for saffron harvesting by targeting quality, only offering extremely high-grade saffron. In addition to descriptions based on how the saffron is picked, saffron may be categorised under the international standard ISO 3632 after laboratory measurement of crocin (responsible for saffron's colour), picrocrocin (taste), and safranal (fragrance or aroma) content. However, often there is no clear grading information on the product packaging and little of the saffron readily available in the UK is labelled with ISO category. This lack of information makes it hard for customers to make informed choices when comparing prices and buying saffron. Under ISO 3632, determination of non-stigma content ("floral waste content") and other extraneous matter such as inorganic material ("ash") are also key. Grading standards are set by the International Organization for Standardization, a federation of national standards bodies. ISO 3632 deals exclusively with saffron and establishes three categories: III (poorest quality), II, and I (finest quality). Formerly there was also category IV, which was below category III.
=== Excretory system === Like reptiles, birds are primarily uricotelic; that is, their kidneys extract nitrogenous waste from their bloodstream and excrete it as uric acid, instead of urea or ammonia, through the ureters into the intestine. Birds do not have a urinary bladder or external urethral opening. With the exception of the ostrich, uric acid is excreted along with faeces as a semisolid waste. However, birds such as hummingbirds can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. They also excrete creatine, rather than creatinine like mammals. This material, as well as the output of the intestines, emerges from the bird's cloaca. The cloaca is a multi-purpose opening: waste is expelled through it, most birds mate by joining cloaca, and females lay eggs from it. In addition, many species of birds regurgitate pellets. It is a common but not universal feature of altricial passerine nestlings (born helpless, under constant parental care) that instead of excreting directly into the nest, they produce a fecal sac. This is a mucus-covered pouch that allows parents to either dispose of the waste outside the nest or to recycle the waste through their own digestive system.
Chemosensory proteins (CSPs) are small soluble proteins which mediate olfactory recognition at the periphery of sensory receptors in insects, similarly to odorant-binding proteins. The typical structure of CSPs is made of six or seven α-helical chains of about 110-120 amino acids (10-12 kDa), including four cysteines that build two small loops, two adjacent disulfide bridges, and a globular "prism-like" functional structure [5]. Three CSP structures have been solved in moths (Mamestra brassicae and Bombyx mori) and locusts (Schistocerca gregaria) [5-8].
Gun rights organizations pledged to challenge the law in court, saying, "Almost the entire bill is a constitutional issue", according to the Illinois State Rifle Association. An Effingham County judge issued a temporary injunction preventing implementation of the law on January 20, 2023. The Illinois Supreme Court ruled the law constitutional and allowed it to take effect. Lawsuits are also pending in federal court and in Crawford County.
Sources: en.wikipedia.org
=== Evacuation of Kabul === In August 2021, elements of the 82nd Airborne Division, particularly the Immediate Response Force, deployed to Afghanistan to secure the evacuation of American diplomats and Afghan Special Immigrant Visa applicants as the Taliban seized land and converged on Kabul. Throughout Operation Allies Refuge, the 82nd Airborne Division served as the Operational Command, Task Force 82. Operation Allies Refuge, led by Major General Chris Donahue, was a combined and joint NATO command post composed of forces representing NATO allied Nations, 1st Brigade Combat Team "Devil", aviation capabilities from the 82nd Combat Aviation Brigade "Pegasus", medical capabilities from the 44th Medical Brigade, riot control capabilities from the 16th Military Police Brigade, 24th Marine Expeditionary Unit, and the 3rd Expeditionary Sustainment Command who oversaw sustainment in the joint operational area from a command post in Kuwait.
Substances found, according to the reports, are 1-Naphthol, naphthalene, Sevin, tarry residues, organochlorines, mercury, chromium, copper, nickel, lead, hexachlorethane, hexachlorobutadiene, pesticide HCH, volatile organic compounds and halo-organics. Many of these contaminants were also found in breast milk of women living near the area. Soil tests were conducted by Greenpeace in 1999. One sample (IT9012) from "sediment collected from drain under former Sevin plant" showed mercury levels to be at "20,000 and 6 million times" higher than expected levels. Organochlorine compounds at elevated levels were also present in groundwater collected from (sample IT9040) a 4.4 metres (14 ft) depth "bore-hole within the former UCIL site". This sample was obtained from a source posted with a warning sign which read "Water unfit for consumption". Chemicals that have been linked to various forms of cancer were also discovered, as well as trichloroethylene, known to impair foetal development, at 50 times above safety limits specified by the U.S. Environmental Protection Agency (EPA). In 2002, an inquiry by Fact-Finding Mission on Bhopal found a number of toxins, including mercury, lead, 1,3,5 trichlorobenzene, dichloromethane and chloroform, in nursing women's breast milk. A 2004 BBC Radio 5 broadcast reported the site is contaminated with toxic chemicals including hexachlorocyclohexane and mercury, held in open containers or loose on the ground.
The actions undertaken in Canada to support incoming aircraft and their occupants were collectively titled Operation Yellow Ribbon. That evening, the Central Intelligence Agency informed President George W. Bush that its Counterterrorism Center had identified the attacks as having been the work of al-Qaeda under Osama bin Laden. The United States responded by invading Afghanistan and launching its Global War on Terror, with the stated goal of eliminating hostile groups it deemed terrorist organizations and the governments the United States identified as supporting them. NATO's invocation of Article 5 of the North Atlantic Treaty—its only usage to date—called upon allies to fight al-Qaeda as well. As U.S. and allied invasion forces swept through Afghanistan, bin Laden eluded them. He denied any involvement until 2004, when excerpts of a taped statement in which he accepted responsibility for the attacks were released. Al-Qaeda's cited motivations included U.S. support of Israel, the presence of U.S. military bases in Saudi Arabia, and sanctions against Iraq. The nearly decade-long manhunt for bin Laden concluded in May 2011, when he was killed during a U.S. military raid in Abbottabad, Pakistan. The war in Afghanistan continued for another decade. The attacks killed 2,977 people, injured thousands more, and gave rise to long-term health consequences while causing at least US$10 billion in infrastructure and property damage.
=== Mucosal surface delivery === Alternatives included aerosol instillation of naked DNA on mucosal surfaces, such as the nasal and lung mucosa, and topical administration of pDNA to the eye and vaginal mucosa. Mucosal surface delivery has also been achieved using cationic liposome-DNA preparations, biodegradable microspheres, attenuated Salmonalla, Shigella or Listeria vectors for oral administration to the intestinal mucosa and recombinant adenovirus vectors.
== Nutritional value == Lysine is an essential amino acid in humans. The human daily nutritional requirement varies from ~60 mg/kg in infancy to ~30 mg/kg in adults. This requirement is commonly met in a western society with the intake of lysine from meat and vegetable sources well in excess of the recommended requirement. In vegetarian diets, the intake of lysine is less due to the limited quantity of lysine in cereal crops compared to meat sources. Given the limiting concentration of lysine in cereal crops, it has long been speculated that the content of lysine can be increased through genetic modification practices. Often these practices have involved the intentional dysregulation of the DAP pathway by means of introducing lysine feedback-insensitive orthologues of the DHDPS enzyme. These methods have met limited success likely due to the toxic side effects of increased free lysine and indirect effects on the TCA cycle. Plants accumulate lysine and other amino acids in the form of seed storage proteins, found within the seeds of the plant, and this represents the edible component of cereal crops. This highlights the need to not only increase free lysine, but also direct lysine towards the synthesis of stable seed storage proteins, and subsequently, increase the nutritional value of the consumable component of crops.
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.
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.