Heptapeptide 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.
Updated 2026-02-08. 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 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.
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.
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 | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
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.
Most structures follow the points-on-a-sphere pattern (or, as if the central atom were in the middle of a polyhedron where the corners of that shape are the locations of the ligands), where orbital overlap (between ligand and metal orbitals) and ligand-ligand repulsions tend to lead to certain regular geometries. The most observed geometries are listed below, but there are many cases that deviate from a regular geometry, e.g. due to the use of ligands of diverse types (which results in irregular bond lengths; the coordination atoms do not follow a points-on-a-sphere pattern), due to the size of ligands, or due to electronic effects (see, e.g., Jahn–Teller distortion):
== Structure == Peptoid oligomers are known to be conformationally unstable, due to the flexibility of the main-chain methylene groups and the absence of stabilizing hydrogen bond interactions along the backbone. Nevertheless, through the choice of appropriate side chains it is possible to form specific steric or electronic interactions that favour the formation of stable secondary structures like helices, especially peptoids with C-α-branched side chains are known to adopt structure analogous to polyproline I helix. Different strategies have been employed to predict and characterize peptoid secondary structure, with the ultimate goal of developing fully folded peptoid protein structures The cis/trans amide bond isomerization still leads to a conformational heterogeneity which doesn’t allow for the formation of homogeneous peptoid foldamers. Nonetheless, scientists were able to find trans-inducer N-Aryl side chains promoting polyproline type II helix, and strong cis-inducer such as bulky naphtylethyl and tert-butyl side chains. It was also found that n→π* interactions can modulate the ratio of cis/trans amide bond conformers, until reaching a complete control of the cis conformer in the peptoid backbone using a functionalizable triazolium side chain.
By the 1801 Treaty of Lunéville, the last Este Duke was compensated with the Breisgau region of the former Further Austrian territories in southwestern Germany, and died in 1803. Following his death, the claims to the no longer existing ducal crown of Modena were inherited by his son-in-law, the Habsburg-Lorraine Archduke Ferdinand of Austria, an uncle of Emperor Francis II.
Sources: en.wikipedia.org
== Interactions == Theoretical considerations suggest calcineurin inhibitors like ciclosporin and tacrolimus might interact with mifamurtide because of their effect on macrophages. High-dose NSAIDs block the mechanism of mifamurtide in vitro. Consequently, the combination of mifamurtide with these types of drugs is contraindicated. However, mifamurtide can be coadministered with low doses of NSAIDs. No evidence suggests mifamurtide interacts with the studied chemotherapeutics, or with the cytochrome P450 system.
From the 17th century, and before modern developments in organic chemistry nomenclature, acetone was given many different names. They included "spirit of Saturn", which was given when it was thought to be a compound of lead and, later, "pyro-acetic spirit" and "pyro-acetic ester". Prior to the name "acetone" being coined by French chemists, it was named "mesit" (from the Greek μεσίτης, meaning mediator) by Carl Reichenbach, who also said that methyl alcohol consisted of mesit and ethyl alcohol. Names derived from mesit include mesitylene and mesityl oxide which were first synthesised from acetone. In 1839, the name "acetone" began to be used, because it was obtained from acetic acid. Unlike many compounds with the acet- prefix which have a 2-carbon chain, acetone has a 3-carbon chain. That has caused confusion because there can not be a ketone with 2 carbons. The prefix refers to acetone's relation to vinegar (acetum in Latin, also the source of the words "acid" and "acetic"), rather than its chemical structure.
The structure of CARD11 involves multiple domains that impact the protein's ability to activate BCL10 and NF-κB activity. CARD11 has a CARD domain, a serine-threonine rich region, is associated with the N-terminus, which is essential for NF-κB signaling activity. The region following the CARD domain is highly coiled. In deleting the CARD domain, all NF-κB signaling activity was prevented. The CARD domain on CARD11 interacts with the CARD domain on BCL10 to initiate the signaling pathway. On the C-terminus of CARD11 there is the MAGUK domain that is associated with the cell membrane. This domain is often referred to as the inhibitory domain. Protein kinase C activates CARD11 by phosphorylating serine residues within the inhibitory domain. CARD11 has been shown to interact with BCL10. This interaction occurs between the CARD domain on BCL10 and the CARD domain on CARD11, and results in signal propagation and NF-κB activation. Human CARD11 genome location and CARD11 gene details page in the UCSC Genome Browser.
Sources: en.wikipedia.org
=== Classification according to chemical structure === Most surfactants comprise "tails" based on saturated or unsaturated hydrocarbons. Fluorosurfactants have fluorocarbon chains. Siloxane surfactants have siloxane chains.
In continuum mechanics and materials science, elasticity is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed. Solid objects will deform when adequate loads are applied to them; if the material is elastic, the object will return to its initial shape and size after removal. This is in contrast to plasticity, in which the object fails to do so and instead remains in its deformed state. The physical reasons for elastic behavior can be quite different for different materials. In metals, the atomic lattice changes size and shape when forces are applied (energy is added to the system). When forces are removed, the lattice goes back to the original lower energy state. For rubbers and other polymers, elasticity is caused by the stretching of polymer chains when forces are applied. Hooke's law states that the force required to deform elastic objects should be directly proportional to the distance of deformation, regardless of how large that distance becomes. This is known as perfect elasticity, in which a given object will return to its original shape no matter how strongly it is deformed. This is an ideal concept only; most materials which possess elasticity in practice remain purely elastic only up to very small deformations, after which plastic (permanent) deformation occurs.
== External links == Official website of the Melbourne Rebels Official website of Athletics Australia "Latest News" - Appointment to Chief Executive Officer Archived 13 February 2008 at the Wayback Machine
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
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.