ACTH fragment is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-01-04. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
| 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 |
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.
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.
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.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Amanita virosa is highly toxic, and has been responsible for severe mushroom poisonings. Eating just one cap of A. virosa is enough to kill an adult human. The symptoms of poisoning generally come several hours after consumption, a delay which may make treatment more difficult. Fruit bodies contain both amatoxins and phallotoxins. Amatoxins consist of at least eight compounds with a similar structure, that of eight amino-acid rings; they were isolated in 1941 by Heinrich O. Wieland and Rudolf Hallermayer of LMU Munich. Of the amatoxins, α-Amanitin is the chief component and along with β-Amanitin is probably responsible for the toxic effects. Their major toxic mechanism is the inhibition of RNA polymerase II, a vital enzyme in the synthesis of messenger RNA (mRNA), microRNA, and small nuclear RNA, (snRNA). Without mRNA essential protein synthesis and hence cell metabolism cease and the cell dies. The liver is the principal organ affected, as it is the organ which is first encountered after absorption in the gastrointestinal tract, though other organs, especially the kidneys, are susceptible. Phallotoxins consist of at least seven compounds, all of which have seven similar peptide rings. Phalloidin was isolated in 1937 by Feodor Lynen, Heinrich Wieland's student and son-in-law, and Ulrich Wieland of LMU Munich. Though phallotoxins are highly toxic to liver cells, they have since been found to have little input into the destroying angel's toxicity as they are not absorbed through the gut. Furthermore, phalloidin is also found in the edible Amanita rubescens.
Folding is a spontaneous process that is mainly guided by hydrophobic interactions, formation of intramolecular hydrogen bonds, van der Waals forces, and it is opposed by conformational entropy. The folding time scale of an isolated protein depends on its size, contact order, and circuit topology. Inside cells, the process of folding often begins co-translationally, so that the N-terminus of the protein begins to fold while the C-terminal portion of the protein is still being synthesized by the ribosome; however, a protein molecule may fold spontaneously during or after biosynthesis. While these macromolecules may be regarded as "folding themselves", the process also depends on the solvent (water or lipid bilayer), the concentration of salts, the pH, the temperature, the possible presence of cofactors and of molecular chaperones. Proteins will have limitations on their folding abilities by the restricted bending angles or conformations that are possible. These allowable angles of protein folding are described with a two-dimensional plot known as the Ramachandran plot, depicted with psi and phi angles of allowable rotation.
Other tools focus on applying structured constraints to inputs, restricting outputs to predefined parameters, or using real-time monitoring mechanisms to identify and address vulnerabilities. These efforts aim to ensure that AI systems are designed with safety and ethical considerations at the forefront, particularly as their use becomes increasingly widespread in critical applications.
== Composition == Liquid aHVP typically contains 55% water, 16% salt, 25% organic substances (thereof 20% protein (amino acids) analyzed as about 3% total nitrogen and 2% amino nitrogen). Many amino acids have either a bitter or sweet taste. In many commercial processes, nonpolar amino acids such as L-leucine and L-isoleucine are often removed to create hydrolysates with a more mellow and less bitter character. D-tryptophan, D-histidine, D-phenylalanine, D-tyrosine, D-leucine, L-alanine, and glycine are known to be sweet, while bitterness is associated with L-tryptophan, L-phenylalanine, L-tyrosine, and L-leucine. When not specified explicitly, the chirality of an amino acid is assumed to be L-, the form found in natural proteins. However, the D-forms do occur in natural food materials in smaller amounts, and the harsh chemical condition of aHVP production is known to flip a small amount of molecules to the D-form. Modern aHVP production has a step for removing tyrosine and leucine from the hydrolysate. Tyrosine is an amino acid susceptible to halogenation during hydrolysis with HCl. Lysine is stable under standard acid hydrolysis, but during heat treatment, the side-chain amino group can react with other compounds, such as reducing sugars, producing Maillard products. The organoleptic properties of HVP is determined not only by amino acid composition, but also by the various aroma-bearing substances other than the amino acids created during the production of both aHVP and eHVP.
Sources: en.wikipedia.org
=== Awards and honours === Knowles was elected a Fellow of the Royal Society (FRS), a Fellow of the American Academy of Arts and Sciences (FAAAS) in 1982, and member of American Philosophical Society in 1988, the American Association for the Advancement of Science, and a Foreign Associate of the National Academy of Sciences. Among his awards are the Royal Society of Chemistry's Charmian Medal, the Bader Award, the Repligen Corporation Award in Chemistry of Biological Processes, the Prelog Medal, the Robert A. Welch Award in Chemistry, the Arthur C. Cope Scholar Award, and the Nakanishi Prize. He was awarded the Davy Medal of the Royal Society, and was an Honorary Fellow of Balliol College and of Wadham College, Oxford. He held honorary degrees from the University of Edinburgh and the Eidgenössische Technische Hochschule in Zürich. He was appointed Order of the British Empire in the 1993 Birthday Honours. He was elected one of nine Trustees of the Howard Hughes Medical Institute in 1998.
The first ionisation energy of an atom is the energy required to remove an electron from it. This varies with the atomic radius: ionisation energy increases left to right and down to up, because electrons that are closer to the nucleus are held more tightly and are more difficult to remove. Ionisation energy thus is minimized at the first element of each period – hydrogen and the alkali metals – and then generally rises until it reaches the noble gas at the right edge of the period. There are some exceptions to this trend, such as oxygen, where the electron being removed is paired and thus interelectronic repulsion makes it easier to remove than expected. In the transition series, the outer electrons are preferentially lost even though the inner orbitals are filling. For example, in the 3d series, the 4s electrons are lost first even though the 3d orbitals are being filled. The shielding effect of adding an extra 3d electron approximately compensates the rise in nuclear charge, and therefore the ionisation energies stay mostly constant, though there is a small increase especially at the end of each transition series. As metal atoms tend to lose electrons in chemical reactions, ionisation energy is generally correlated with chemical reactivity, although there are other factors involved as well.
The most traditional preparation is a study skin, in which almost all of the body inside the skin is removed and replaced with cotton so that the final result resembles a bird lying on its back with its wings folded. Borax is used as the preferred preservative as it is low in toxicity. This stereotypic posture was developed to enable many skins to be kept together in cabinets to protect them from insect and light damage. If a complete skeleton is desired, a flat skin may be prepared: all bones, muscle, digestive and other soft tissue is carefully removed and the feathers and skin are stretched flat and dried.
=== Aplastic anemia === The most serious side effect of chloramphenicol treatment is aplastic anaemia ('AA'). This effect is rare but sometimes fatal. The risk of AA is high enough that alternatives should be strongly considered. Treatments are available but expensive. No way exists to predict who may or may not suffer this side effect. The effect usually occurs weeks or months after treatment has been stopped, and a genetic predisposition may be involved. It is not known whether monitoring the blood counts of patients can prevent the development of aplastic anaemia, but patients are recommended to have a baseline blood count with a repeat blood count every few days while on treatment. Chloramphenicol should be discontinued if the complete blood count drops. The highest risk is with oral chloramphenicol (affecting 1 in 24,000–40,000) and the lowest risk occurs with eye drops (affecting less than one in 224,716 prescriptions).
=== Techdirt === In January 2017, Ayyadurai, again represented by Harder, filed a $15 million libel lawsuit on similar grounds against Techdirt founder Mike Masnick and two other parties for a series of articles published beginning in September 2014. In February, Masnick, represented by the firm Prince Lobel, filed two motions to dismiss. One motion argued that the articles were constitutionally protected opinion and written about a public figure without actual malice. The second motion asked for dismissal under California's anti-SLAPP law that compensates defendants for some legal expenses. In September 2017, United States District Judge F. Dennis Saylor dismissed the defamation claims against Techdirt, but declined to strike the complaint under the anti-SLAPP law. In his ruling, Saylor wrote that definitions of "email" vary widely. Therefore, "whether plaintiff's claim to have invented e-mail is 'fake' depends upon the operative definition of 'e-mail.' Because the definition does not have a single, objectively correct answer, the claim is incapable of being proved true or false." The two parties filed cross-appeals with the U.S. Court of Appeals for the First Circuit but settled out of court in May 2019, with each side agreeing to pay their own legal costs and Techdirt's articles to remain online with an added link to a rebuttal on Ayyadurai's website.
Sources: en.wikipedia.org
L-homoserine to form H2O, NH3 and 2-oxobutanoate L-cystine, producing cysteine hydropersulfide, pyruvate and NH3 L-cysteine producing pyruvate, NH3 and H2S In some bacteria and mammals, including humans, this enzyme takes part in generating hydrogen sulfide. Hydrogen sulfide is one of a few gases that was recently discovered to have a role in cell signaling in the body.
=== Lithium === Tritium is most often produced in nuclear reactors by neutron activation of lithium-6. The release and diffusion of tritium and helium produced by the fission of lithium can take place within ceramics known as breeder ceramics. Production of tritium from lithium-6 in such breeder ceramics is possible with neutrons of any energy, though the cross section is higher when the incident neutrons have lower energy, reaching more than 900 barns for thermal neutrons. This is an exothermic reaction, yielding 4.8 MeV. In comparison, fusion of deuterium with tritium releases about 17.6 MeV. For applications in proposed fusion energy reactors, such as ITER, pebbles consisting of lithium bearing ceramics including Li2TiO3 and Li4SiO4, are being developed for tritium breeding within a helium-cooled pebble bed, also known as a breeder blanket.
Naturally occurring nickel (28Ni) consists of five stable isotopes; 58Ni, 60Ni, 61Ni, 62Ni and 64Ni; 58Ni is the most abundant at over 68%. 26 radioisotopes have been characterized; the most stable are 59Ni with a half-life of 81,000 years, 63Ni with a half-life of 101 years, and 56Ni at 6.075 days. All the other radioactive isotopes have half-lives of less than 60 hours and most of these have half-lives of less than 30 seconds. This element also has 11 known meta states.
== Controversies == In December 2016, Zydus Discovery DMCC, a research subsidiary Zydus Lifesciences, was cited by the US FDA for deliberately misbranding saroglitazar. In a December 21, 2016, letter to the company, the US FDA asked it to stop using broad statements, such as the "world's first" and to stop suggesting that the drug is approved throughout the world, including in the United States, when that is not true.
In 2017, Dmitry Sanakoyev, who served as separatist Prime Minister of South Ossetia in 2001, stated that Kokoity's regime began to plan the war in 2002. He stated: "It was 2002, before Saakashvili's rise to power. Military enlistment offices were involved. 2500 people were called to arms within two months. People who received USD 9, were offered to receive USD 50 – who would not agree? Then these people were started to be sent to the checkpoint. And when a person goes there, he drinks. And then shows his bravado, starts shooting. There is a response from the place he was shooting at. And primitive provocations start."
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 peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.