Pro-Gly-Pro tail raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-03. Anything still debated is marked as such rather than presented as settled.
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.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Calculated for the free peptide |
| Molar mass | 813.9 g/mol | Anhydrous free base |
| Peptide class | Synthetic heptapeptide | ACTH(4-10) analogue |
| Parent fragment | ACTH(4-10) | Adrenocorticotropic hormone segment |
| Developmental origin | Institute of Molecular Genetics, Moscow | Work began in the 1980s |
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
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.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
=== Brand names === Brand names of carteolol include Arteolol, Arteoptic, Calte, Cartéabak, Carteol, Cartéol, Cartrol, Elebloc, Endak, Glauteolol, Mikelan, Ocupress, Poenglaucol, Singlauc, and Teoptic.
A plebiscite on whether the Sanitary Board should have an official or unofficial majority was held in Hong Kong in June 1896. The result of the plebiscite was overwhelmingly for unofficial majority, however no constitutional changes were made for Sanitary Board, though the constitutions of the Executive and Legislative Council were changed as unofficial members were added as a result. The 1896 plebiscite is on record the only referendum conducted by the Hong Kong Government and could be seen as part of the first major debate on the constitutional reform in the crown colony during the 1890s. It was much earlier than the Governor Mark Aitchison Young's Young Plan in the 1940s and 1950s and the rise of the modern pro-democracy camp in the 1980s.
ASBMB Avanti Award for Lipid Research (1998) Elected to the American Academy of Arts and Sciences (1999) Heinrich Wieland Prize for Lipid Research (2000) Elected to the National Academy of Sciences (2001) Caledonian Prize from the Royal Society of Edinburgh (2002) Pezcoller-AACR International Award for Cancer Research (2005) Rolf Luft Award of the Karolinska Institute (2009) Pasrow Prize for Cancer Research (2011) Breakthrough Prize in Life Sciences (2013) Jacobaeus Prize for Diabetes Research, from the Karolinska Institute (2013) Elected to the Institute of Medicine of the National Academies (2014) AACR Princess Takamatsu Memorial Lectureship (2015) Ross Prize in Molecular Medicine (2015) Canada Gairdner International Award (2015) Elected to European life sciences academy EMBO (2015) The Association of American Cancer Institutes Distinguished Scientist Award (2015) Thomson Reuter's "The World's Most Influential Scientific Minds 2015". The Wolf Prize in Medicine (2016) The Hope Funds Award of Excellence in Basic Science (2016) Louisa Gross Horwitz Prize (2019) He appeared in the 60 Minutes program "Is sugar toxic?".
=== Blood test === see also: blood doping The blood test detects illegal performance enhancement drugs through the measurement of indicators that change with the use of recombinant human erythropoietin:
The samples were found to be "masses of virtually pure collagen" and not to have the "biochemical characteristics of invertebrate collagen, nor the collagen fiber arrangement of octopus mantle." The results suggest the samples are "the remains of the skin of an enormous warm-blooded vertebrate." The authors conclude that "there is no evidence to support the existence of Octopus giganteus" and concur with Verrill (1897) and Lucas (1897) that the St. Augustine carcass was "the remains of a whale, likely the entire skin [blubber layer] . . . nothing more or less."
Sources: en.wikipedia.org
== Further reading == Bryant, Alfred T. (1964). A History of the Zulu and Neighbouring Tribes. Cape Town: C. Struik. p. 157. Cana, Frank Richardson (1911). "Zululand" . Encyclopædia Britannica. Vol. 28 (11th ed.). pp. 1050–1055. Morris, Donald R. (1965). The Washing of the Spears: the Rise of the Zulu Nation. New York: Simon and Schuster. p. 655. Deflem, Mathieu. (1999). Warfare, Political Leadership, and State Formation: The Case of the Zulu Kingdom, 1808–1879. Ethnology 38(4):371–391. Knight, Ian. (2010). Zulu Rising: The Epic Story of Isandlwana and Rorke's Drift, London: Macmillan. ISBN 978-1-405-09185-5
signaling PRRs that activate gene transcriptional mechanisms that lead to cellular activation, endocytic PRRs that function in pathogen binding and phagocytosis, and secreted PRRs that usually function as opsonins or activators of complement. The recognition and clearance of invading microorganisms occurs through both opsonin-dependent and opsonin–independent pathways. The molecular mechanisms facilitating opsonin-dependent phagocytosis are different for specific opsonin/receptor pairs. For example, phagocytosis of IgG-opsonized pathogens occurs through the Fcγ receptors (FcγR), and involves phagocyte extensions around the microbe, resulting in the production of pro-inflammatory mediators. Conversely, complement receptor-mediated pathogen ingestion occurs without observable membrane extensions (particles just sink into the cell) and does not generally results in an inflammatory mediator response. Following internalization, the microbe is enclosed in a vesicular phagosome which then undergoes fusion with primary or secondary lysosomes, forming a phagolysosome. There are various mechanisms that lead to intracellular killing; there are oxidative processes, and others independent of the oxidative metabolism. The former involves the activation of membrane enzyme systems that lead to a stimulation of oxygen uptake (known as the respiratory burst), and its reduction to reactive oxygen intermediates (ROIs), molecular species that are highly toxic for microorganisms.
Nuclear magnetic resonance was first described and measured in molecular beams by Isidor Rabi in 1938, by extending the Stern–Gerlach experiment, and in 1944, Rabi was awarded the Nobel Prize in Physics for this work. In 1946, Felix Bloch and Edward Mills Purcell expanded the technique for use on liquids and solids, for which they shared the Nobel Prize in Physics in 1952. Russell H. Varian filed the "Method and means for correlating nuclear properties of atoms and magnetic fields", U.S. patent 2,561,490 on October 21, 1948 and was accepted on July 24, 1951. Varian Associates developed the first NMR unit called NMR HR-30 in 1952. Purcell had worked on the development of radar during World War II at the Massachusetts Institute of Technology's Radiation Laboratory. His work during that project on the production and detection of radio frequency power and on the absorption of such RF power by matter laid the foundation for his discovery of NMR in bulk matter. Rabi, Bloch, and Purcell observed that magnetic nuclei, like 1H and 31P, could absorb RF energy when placed in a magnetic field and when the RF was of a frequency specific to the identity of the nuclei. When this absorption occurs, the nucleus is described as being in resonance. Different atomic nuclei within a molecule resonate at different (radio) frequencies in the same applied static magnetic field, due to various local magnetic fields.
=== Structure activity relationship === The structure of Benzoquinones may explain their toxicity. Benzoquinones are electrophilic and can undergo reactions with nucleophilic groups, for instance on amino acids, altering structure and function of the proteins. Due to the Cl groups on the quinone ring in DCBQ, the overall electrophilicity of the HBQ is increased, which causes higher reactivity with nucleophilic groups, such as glutathione, proteins, and nucleic acids. If DCBQ reacts with glutathione they form conjugates, lowering GSH levels in the cell, which might lead to GSH depletion.
Sources: en.wikipedia.org
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.
It is registered for clinical use in Russia and a few other countries, typically as a nasal drop formulation. It does not hold approval from the United States Food and Drug Administration or the European Medicines Agency. Outside those markets it is generally handled as a research chemical.
The compound was developed in Moscow and the earliest studies were conducted there, so the primary literature is largely in Russian-language journals. Translation and indexing have been incomplete, which limits access for outside researchers. Independent groups have since published some work, but the total volume remains modest.
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.