Pro-Gly-Pro tail comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-09-29. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
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.
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The coastal taipan (Oxyuranus scutellatus) is a large, highly venomous elapid, whose range includes the southern parts of the island of New Guinea and extends in an arc along the east coast of Australia from northeastern New South Wales through Queensland and across the northern parts of the Northern Territory to northern Western Australia. This snake can be highly aggressive when cornered and will actively defend itself. They are extremely nervous and alert snakes, and any movement near them is likely to trigger an attack. When threatened, this species adopts a loose striking stance with its head and forebody raised. It inflates and compresses its body laterally (not dorso-ventrally like many other species) and may also spread the back of its jaws to give the head a broader, lance-shaped appearance. In this position the snake will strike without much provocation, inflicting multiple bites with extreme accuracy and efficiency. The muscular lightweight body of the taipan allows it to hurl itself forwards or sideways and reach high off the ground, and such is the speed of the attack that a person may be bitten several times before realizing the snake is there. This snake is considered to be one of the most venomous in the world. Ernst and Zug et al. (1996) and the Australian venom and toxin database both list an LD50 value of 0.106 mg/kg for subcutaneous injection. Engelmann and Obst (1981) list a value of 0.12 mg/kg SC, with an average venom yield of 120 mg per bite and a maximum record of 400 mg.
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Despite initial successes, however, Gericke realized that the time was not yet ripe for the general technical application and commercial use of hydroponics for producing crops. He also wanted to make sure all aspects of hydroponic cultivation were researched and tested before making any of the specifics available to the public. Reports of Gericke's work and his claims that hydroponics would revolutionize plant agriculture prompted a huge number of requests for further information. Gericke had been denied use of the university's greenhouses for his experiments due to the administration's skepticism, and when the university tried to compel him to release his preliminary nutrient recipes developed at home, he requested greenhouse space and time to improve them using appropriate research facilities. While he was eventually provided greenhouse space, the university assigned Hoagland and Arnon to re-evaluate Gericke's claims and show his formula held no benefit over soil grown plant yields, a view held by Hoagland. Because of these irreconcilable conflicts, Gericke left his academic position in 1937 in a climate that was politically unfavorable and continued his research independently in his greenhouse. In 1940, Gericke, whose work is considered to be the basis for all forms of hydroponic growing, published the book, Complete Guide to Soilless Gardening. Therein, for the first time, he published his basic formulas involving the macro- and micronutrient salts for hydroponically grown plants.
Sources: en.wikipedia.org
The US government responded by saying the Rhodesian mission and its staff had no official diplomatic status and violated no US laws. Portugal pursued a middle path with Rhodesia. While not officially recognising Rhodesia under Ian Smith, the government of António Salazar did permit Rhodesia to establish a representative mission in Lisbon, and permitted Rhodesian exports and imports through their province of Mozambique. The Portuguese government in power at that time, authoritarian and ardently anti-communist, gave active behind-the-scenes support in Rhodesia's fight against the guerrilla groups. South Africa, itself under international pressure as a white minority government, pursued a policy of détente with the black African states at the time. These states wanted South Africa to pressure Ian Smith to accept a faster transition to majority rule in Rhodesia, in return for pledges of non-interference in South Africa's internal affairs. Prime Minister John Vorster, believing majority rule in Rhodesia would lead to international acceptance for South Africa, used a number of tactics to pressure Smith. The South African government held up shipments of fuel and ammunition and pulled out friendly South African forces from Rhodesia. The combined loss of Mozambique and the loss of support from South Africa dealt critical blows to the Rhodesian government.
=== Applications === The most widespread application of copper-free click chemistry is in biological imaging in live cells or animals using an azide-tagged biomolecule and a cyclooctyne bearing an imaging agent. Fluorescent keto and oxime variants of DIBO are used in fluoro-switch click reactions in which the fluorescence of the cyclooctyne is quenched by the triazole that forms in the reaction. On the other hand, coumarin-conjugated cyclooctynes such as coumBARAC have been developed such that the alkyne suppresses fluorescence while triazole formation increases the fluorescence quantum yield by ten-fold.
== Further reading == Rappoport, n.; Paik, P.; Oskotsky, B.; Tor, R.; Ziv, E.; Zaitlen, N.; Butte, A. (2018). "Comparing Ethnicity-Specific Reference Intervals for Clinical Laboratory Tests from EHR Data". The Journal of Applied Laboratory Medicine. 3 (3): 366–377. bioRxiv 10.1101/213892. doi:10.1373/jalm.2018.026492. PMC 8404742. PMID 33636914.
The GHRHR is a member of the secretin family of G protein-coupled receptors, and is located on chromosome 7 in humans. This protein is transmembranous with seven folds, and its molecular weight is approximately 44 kD.
Sources: en.wikipedia.org
=== Mass spectrometry === Mass spectrometry provides information about the structure and composition of the complexes. Spectra for metal polycarbonyls are often easily interpretable, because the dominant fragmentation process is the loss of carbonyl ligands (m/z = 28).
The Expanded Program on Immunization (EPI) in the Philippines began in 1976 through Presidential Decree No. 996 signed by President Ferdinand Marcos. And, in 1986, made a response to the Universal Child Immunization goal. The four major strategies include:
=== July === July 27, 2011: United Kingdom After figures showed that the 0.5% contraction in Q4 2010 was cancelled out by a 0.5% rise in Q1 2011, growth estimates from the ONS suggest that the growth in the UK is slowing down, after figures of 0.2% GDP increase was posted. Sovereign debt in the Eurozone and EU cause the stock market to crash from a FTSE-100 high of 6100 points to just above 5000.
== Biography == Barrett was born in 1963 in Toronto, Ontario, Canada, to a working poor family and was the first member of her extended family to attend university. After graduating from the University of Toronto with honors, she pursued a Ph.D. in clinical psychology at the University of Waterloo with the goal of becoming a therapist, until a frustrating puzzle sidetracked her from a clinical career. As a graduate student, she failed eight times to replicate a simple experiment, finally realizing that her seeming failed attempts were, in fact, successfully replicating a previously undiscovered phenomenon. The resulting research direction became her life's work: understanding the nature of emotion in the brain. Following a clinical internship at the University of Manitoba Medical School, she held professorships in psychology at Penn State University, Boston College, and Northeastern University.[1] Over two decades, she transitioned from clinical psychology into social psychology, psychophysiology, cognitive science, and cognitive neuroscience. Barrett is most inspired by William James, Wilhelm Wundt, and Charles Darwin. In 2019–2020, she served as president of the Association for Psychological Science. From 2018–2025, she was ranked in the top one percent of the most-cited scientists in the world over a ten-year period. In addition to academic work, Barrett has written two science books for the public, How Emotions are Made (2017) and Seven and a Half Lessons About the Brain (2020), and her TED talk was among the 25 most popular worldwide in 2018.
atom of cysteine residues to anchor proteins to cellular membranes. Unlike the GPI and myritoyl anchors, these groups are not necessarily added at the termini. carboxylation A relatively rare modification that adds an extra carboxylate group (and, hence, a double negative charge) to a glutamate side chain, producing a Gla residue. This is used to strengthen the binding to "hard" metal ions such as calcium. ADP-ribosylation The large ADP-ribosyl group can be transferred to several types of side chains within proteins, with heterogeneous effects. This modification is a target for the powerful toxins of disparate bacteria, e.g., Vibrio cholerae, Corynebacterium diphtheriae and Bordetella pertussis. ubiquitination and SUMOylation Various full-length, folded proteins can be attached at their C-termini to the sidechain ammonium groups of lysines of other proteins. Ubiquitin is the most common of these, and usually signals that the ubiquitin-tagged protein should be degraded. Most of the polypeptide modifications listed above occur post-translationally, i.e., after the protein has been synthesized on the ribosome, typically occurring in the endoplasmic reticulum, a subcellular organelle of the eukaryotic cell. Many other chemical reactions (e.g., cyanylation) have been applied to proteins by chemists, although they are not found in biological systems.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
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.