neurotrophic factor raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-09-16. 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 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.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
| 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.
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.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
When stimulated in Oplophorus gracilirostris, OpLuc is secreted from the base of legs and antennae of the deep-sea shrimp as a defense mechanism. This mechanism causes O.gracilirostris release a luminous, bright blue luciferase cloud. There are many species of shrimp which display similar bioluminescence.
periodic table of the elements Also simply the periodic table. A tabular arrangement of the chemical elements organized by their atomic number, electron configuration, and other chemical properties, whose adopted structure shows periodic trends and is used by chemists to derive relationships between various elements as well as predict the properties and behaviors of undiscovered or newly synthesized elements. The first periodic table of the elements was published by Russian chemist Dmitri Mendeleev in 1869.
=== Neutral amino acid substitution === While substitution of a base in a noncoding area of a genome may make little difference and be considered neutral, base substitutions in or around genes may impact the organism. Some base substitutions lead to synonymous mutation and no difference in the amino acid translated as noted above. However, a base substitution can also change the genetic code so that a different amino acid is translated. This sort of substitution usually has a negative effect on the protein being formed and will be eliminated from the population through purifying selection. However, if the change has a positive influence, the mutation may become more and more common in a population until it becomes a fixed genetic piece of that population. Organisms changing via these two options comprise the classic view of natural selection. A third possibility is that the amino acid substitution makes little or no positive or negative difference to the affected protein. Proteins demonstrate some tolerance to changes in amino acid structure. This is somewhat dependent on where in the protein the substitution takes place. If it occurs in an important structural area or in the active site, one amino acid substitution may inactivate or substantially change the functionality of the protein. Substitutions in other areas may be nearly neutral and drift randomly over time.
== Isothermal Kovats retention index == The Kovats index applies to organic compounds. The method interpolates peaks between bracketing n-alkanes. The Kovats index of n-alkanes is 100 times their carbon number, e.g. the Kovats index of n-butane is 400. The Kovats index is dimensionless, unlike retention time or retention volume. For isothermal gas chromatography, the Kovats index is given by the equation:
Sources: en.wikipedia.org
Asking if it were possible to predict if the wartime alliance would fall apart within a matter of months, leaving in its place nearly a half century of cold war, Gaddis wrote in a 1997 essay, "Geography, demography, and tradition contributed to this outcome but did not determine it. It took men, responding unpredictably to circumstances, to forge the chain of causation; and it took [Stalin] in particular, responding predictably to his own authoritarian, paranoid, and narcissistic predisposition, to lock it into place". Historians have also considered interpersonal dynamics in the causes of the Cold War. Discussion on politics as personal has stressed the importance of the personalities and emotions of the Big Three in the breakdown of their wartime alliance. Frank Costigliola has emphasised how the Cold War blurred the lines between the personal and political, with Roosevelt's death marking a turning point in US-Soviet relations. Costigliola maintains that Roosevelt's personal rapport and diplomacy with Stalin maintained cooperation, while Truman, taking a more aggressive policy, a shift driven by his eagerness to prove himself as president, disrupted this cooperation. Costigliola argues that this shift in leadership brought "emotional disposition" and "divisive discourses", contributing to the breakdown of the Grand Alliance, and accelerating the onset of the Cold War. Global historian Prasenjit Duara has placed the issue in a global context:
Insulin-like growth factor 2 (IGF-2) is a hormone that in humans is encoded by the IGF2 gene. This hormone functions as one of the primary growth hormones during fetal development, which differs from the related hormone IGF-1 which is the major growth factor in adults (whose release is stimulated by growth hormone). As its name suggests, it shares structural similarity to insulin.
The Arabidopsis serpin, AtSerpin1 (At1g47710; 3LE2), mediates set-point control over programmed cell death by targeting the 'Responsive to Desiccation-21' (RD21) papain-like cysteine protease. AtSerpin1 also inhibits metacaspase-like proteases in vitro. Two other Arabidopsis serpins, AtSRP2 (At2g14540) and AtSRP3 (At1g64030) appear to be involved in responses to DNA damage.
== External links == Richard L.M. Synge on Nobelprize.org Synge's Nobel Lecture Applications of Partition Chromatography Sidney Elsden (21 June 2016), Richard Laurence Millington Synge (PDF), archived from the original (PDF) on 29 October 2007, retrieved 17 October 2007
Wiechelman, K.; Braun, R. & Fitzpatrick, J. (1988). "Investigation of the bicinchoninic acid protein assay: Identification of the groups responsible for color formation". Anal. Biochem. 175 (1): 231–7. doi:10.1016/0003-2697(88)90383-1. PMID 3245570. Stoscheck, CM. (1990). "6". Quantitation of Protein. Methods in Enzymology. Vol. 182. pp. 50–69. doi:10.1016/0076-6879(90)82008-P. ISBN 9780121820831. PMID 2314256.
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.
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.