A practical reference on neuropeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-03-17. Anything still debated is marked as such rather than presented as settled.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
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.
=== Physical properties === Indigoidine is a blue amorphous powder that is insoluble in water and most other solvents, but dissolves in hydrochloric acid, producing a royal blue color, and in hot sulfuric acid, producing an orange-brown color.
=== Civilian === Although the majority of the world's submarines are military, there are some civilian submarines, which are used for tourism, exploration, oil and gas platform inspections, and pipeline surveys. Some are also used in illegal activities. The Submarine Voyage ride opened at Disneyland in 1959, but although it ran under water, it was not a true submarine, as it ran on tracks and was open to the atmosphere. The first tourist submarine was Auguste Piccard, which went into service in 1964 at Expo64. By 1997, there were 45 tourist submarines operating around the world. Submarines with a crush depth in the range of 400–500 feet (120–150 m) are operated in several areas worldwide, typically with bottom depths around 100 to 120 feet (30 to 37 m), with a carrying capacity of 50 to 100 passengers. In a typical operation a surface vessel carries passengers to an offshore operating area and loads them into the submarine. The submarine then visits underwater points of interest such as natural or artificial reef structures. To surface safely without danger of collision the location of the submarine is marked with an air release and movement to the surface is coordinated by an observer in a support craft. A recent development is the deployment of so-called narco-submarines by South American drug smugglers to evade law enforcement detection. Although they occasionally deploy true submarines, most are self-propelled semi-submersibles, where a portion of the craft remains above water at all times.
The plot of Black Mesa is almost identical to Half-Life's storyline. Like in the original game, the player controls Gordon Freeman, a theoretical physicist working at the Black Mesa Research Facility. He is tasked to place a sample of anomalous material into an Anti-Mass Spectrometer for analysis, using the Mark IV Hazardous Environment Suit (HEV Suit) to do so safely. However, the sample causes a "resonance cascade", devastating the facility and creating an interdimensional rift to an alien dimension called Xen, bringing its alien creatures to Earth. Freeman survives the incident, finds other survivors, and is tasked to make his way to the surface to call for help. Upon reaching the surface, however, he finds that the facility is being cleansed of any and all biological organisms – human or alien – by the military. Freeman learns from the surviving scientists the only way to stop the alien invasion is to cross over to Xen, a border world connecting different universes, and destroy the entity called the Nihilanth keeping the rift open. Freeman is teleported to Xen, destroys the Nihilanth, and ends the alien invasion. He is then detained by the G-Man, a mysterious interdimensional agent who claims his "employers" wish to hire Freeman. If he accepts, Freeman is placed into stasis; if not, he is teleported to his death.
Specialized groups of neuroendocrine cells can be found at the base of the third ventricle in the brain (in a region called the hypothalamus). This area controls most anterior pituitary cells and thereby regulates functions in the entire body, like responses to stress, cold, sleep, and the reproductive system. The neurons send processes to a region connecting to the pituitary stalk and releasing hormones are delivered into the bloodstream. They are carried by portal vessels to the pituitary cells where they may stimulate, inhibit, or maintain the function of a particular cell type.
On March 11, 1997, National Semiconductor Corporation announced the US$550 million sale of a reconstituted Fairchild to the management of Fairchild with the backing of Sterling LLC, a unit of Citicorp Venture Capital. Fairchild carried with it what was mostly the Standard Products group previously segregated by Amelio. Incidentally, the effective price of acquisition of Cyrix was also US$550 million. On November 17, 1997, National Semiconductor and Cyrix announced the merger of the companies. Cyrix would become an autonomous wholly owned subsidiary. Halla had earlier emphasized that National was after the low-end CPU market as part of the system-on-a-chip pursuit and therefore would not place emphasis on Cyrix's current development of high-end 6x86MX design. However, Cyrix later announced that its merger with National Semiconductor would not change its development or marketing plans. The acquisition of an independent-minded Cyrix subsequently turned National Semiconductor from a collaborator into a competitor with Intel. National lost its business with Intel. Intel reinstated the relationship after the sale of Cyrix. The acquisition of Cyrix also carried with it a business obligation to use the IBM Microelectronics Division to fabricate the Cyrix chips, as well as technical constraint to do the same, while National Semiconductor had plans to transfer their fabrication to its South Portland fab. National incurred huge losses in its processor business and announced the sale of Cyrix to VIA in 1999.
Sources: en.wikipedia.org
Prodigiosin is a red dye produced by many strains of the bacterium Serratia marcescens, as well as other Gram-negative, gamma proteobacteria such as Vibrio psychroerythrus and Hahella chejuensis. It is responsible for the pink tint occasionally found in grime that accumulates on porcelain surfaces such as bathtubs, sinks, tiles and toilet bowls. It is in the prodiginine family of compounds which are produced in some Gram-negative gamma proteobacteria, as well as select Gram-positive Actinobacteria (e.g. Streptomyces coelicolor). The name prodigiosin is derived from prodigious (i.e. something marvelous).
== FPR3 function == The overall function of FPR3 is quite unclear. Compared to FPR1 and FPR2, FPR3 is highly phosphorylated (a signal for receptor inactivation and internalization) and more localized to small intracellular vesicles. This suggests that FPR3 rapidly internalizes after binding its ligands and thereby may serve as a "decoy" receptor to reduce the binding of its ligands to FRP1 and FRP2 receptors.
Mahathir reclaimed Carcosa Hill, which had been given to the British by Tunku Abdul Rahman after independence as a sign of good faith, and was home to the British High Commissioner's residence. Mahathir developed a close friendship with Thatcher, leading to strengthened bilateral relations between the two countries during their tenure. Thatcher once praised Mahathir as a truly remarkable national leader and described Malaysia as a textbook example of how to build a prosperous nation. After Thatcher's 1985 visit to Malaysia, bilateral ties improved significantly. Key progress included enhanced trade, particularly in palm oil exports and British technology imports, as well as increased educational cooperation through scholarships for Malaysian students in the UK. Malaysia-UK relations were back on track, leading to Malaysia being chosen to host two major world events — the Commonwealth Heads of Government Meeting in Langkawi in 1989 and the Commonwealth Games in 1998. Mahathir spoke of his good working relationship with Thatcher, saying, "Malaysians should remember that she visited Kuala Lumpur three times — no other British PM has done this before or since." During John Major's visit to Malaysia in September 1993, five memorandums of understanding, involving several billion ringgit, were signed between Malaysian and British companies.
== Spiking studies == In many cases, the concentration of viruses in a given sample is extremely low. In other extraction processes, low levels of impurity may be negligible, but because viruses are infective impurities, even one viral particle may be enough to ruin an entire process chain. It is for this reason that special measures must be taken to determine the appropriate removal or inactivation method for whatever type of virus is being extracted from whatever type of solution. Spiking studies were created specifically for this purpose. A spiking study is a study done in order to determine the possible methods of viral removal or inactivation. The results of these studies are numerical and, based on these numbers, researchers can determine whether or not the process on which the study was conducted will be suitable for the viruses they are trying to extract and the solution from which they are trying to extract them.
Sources: en.wikipedia.org
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
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.