ACTH 片段 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 2025-10-16. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
| 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. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
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.
Aberrant activation of Akt, either via PI3K or independently of PI3K, is often associated with malignancy. Studies have identified gene amplification of the Akt isoforms in many types of cancer, including glioblastoma, ovarian, pancreatic and breast cancers. Akt is also up-regulated in terms of mRNA production in breast and prostate cancer. Functional inactivation of PTEN, the major PI3K antagonist, can occur in cancer cells by point mutation, gene deletion or epigenetic mechanisms. Mutation in the pathway can also affect receptor tyrosine kinases, growth factors, Ras and the PI3K p110 subunit, leading to abnormal signaling activity. Therefore, many of the proteins in the pathway are targets for cancer therapeutics. In addition to its effects on cell survival and cell cycle progression, the PI3K-Akt pathway promotes other characteristics of cancer cells. Hyperactivity of the pathway promotes the epithelial-mesenchymal transition (EMT) and metastasis due to its effects on cell migration.
The overall fold of the KaiA monomer is that of a four-helix bundle, which forms a dimer in the known structure. KaiA functions as a homodimer. Each monomer is composed of three functional domains: the N-terminal amplitude-amplifier domain, the central period-adjuster domain and the C-terminal clock-oscillator domain. The N-terminal domain of KaiA, from cyanobacteria, acts as a pseudo-receiver domain, but lacks the conserved aspartyl residue required for phosphotransfer in response regulators. The C-terminal domain is responsible for dimer formation, binding to KaiC, enhancing KaiC phosphorylation and generating the circadian oscillations. The KaiA protein from Anabaena sp. (strain PCC 7120) lacks the N-terminal CheY-like domain. KaiB adopts an alpha-beta meander motif and is found to be a dimer or a tetramer. KaiC belongs to a larger family of proteins; it performs autophosphorylation and acts as its own transcriptional repressor. It binds ATP.
Fast parallel proteolysis (FASTpp) is a method to determine the thermostability of proteins by measuring which fraction of protein resists rapid proteolytic digestion. Proteolysis is widely used in biochemistry and cell biology to probe protein structure. In "limited trypsin proteolysis", low amounts of protease digest both folded and unfolded protein but at largely different rates: unstructured proteins are cut more rapidly, while structured proteins are cut at a slower rate (sometimes by orders of magnitude). Recently, several other assays of protein stability based on proteolysis have been proposed, exploiting other proteases with high specificity for cleaving unfolded proteins. These include Pulse Proteolysis, Proteolytic Scanning Calorimetry and FASTpp.
The composition and rate of CSF generation are influenced by hormones and the content and pressure of blood and CSF. For example, when CSF pressure is higher, there is less of a pressure difference between the capillary blood in choroid plexuses and CSF, decreasing the rate at which fluids move into the choroid plexus and CSF generation. The autonomic nervous system influences choroid plexus CSF secretion, with activation of the sympathetic nervous system decreasing secretion and the parasympathetic nervous system increasing it. Changes in the pH of the blood can affect the activity of carbonic anhydrase, and some drugs (such as furosemide, acting on the Na-K-Cl cotransporter) have the potential to impact membrane channels.
Amyloid beta (Aβ, Abeta or beta-amyloid) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid-beta precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ in a cholesterol-dependent process and substrate presentation. Both neurons and oligodendrocytes produce and release Aβ in the brain, contributing to formation of amyloid plaques. Aβ molecules can aggregate to form flexible soluble oligomers which may exist in several forms. It is now believed that certain misfolded oligomers (known as "seeds") can induce other Aβ molecules to also take the misfolded oligomeric form, leading to a chain reaction akin to a prion infection. The oligomers are toxic to nerve cells. The other protein implicated in Alzheimer's disease, tau protein, also forms such prion-like misfolded oligomers, and there is some evidence that misfolded Aβ can induce tau to misfold. A study has suggested that APP and its amyloid potential is of ancient origins, dating as far back as early deuterostomes.
Sources: en.wikipedia.org
The protein encoded by this gene is a member of the STAT protein family. In response to cytokines and growth factors, STAT family members are phosphorylated by the receptor associated kinases, and then form homo- or heterodimers that translocate to the cell nucleus where they act as transcription activators. In response to IFN, this protein forms a complex with STAT1 and IFN regulatory factor family protein p48 (IRF9) and form ISGF-3 (IFN-stimulated gene factor-3), in which this protein acts as a transactivator, but lacks the ability to bind DNA directly. The protein mediates innate antiviral activity. Mutations in this gene result in Immunodeficiency 44. ISGF-3 proceeds the activation of genes via the IFN-stimulated response element (ISRE). ISRE-driven genes include Ly-6C, the double-stranded RNA kinase (PKR), 2´ to 5´ oligoadenylate synthase (OAS), MX and potentially MHC class I. Transcription adaptor P300/CBP (EP300/CREBBP) has been shown to interact specifically with this protein, which is thought to be involved in the process of blocking IFN-alpha response by adenovirus. STAT2 knockout mice are unresponsive to type I IFN and extremely vulnerable to viral infection. They indicate the loss of the type I IFN autocrine loop and several defects in macrophages and T cell responses. Stat2-/- cells show differences in the biological response to IFN-α.
The society publishes three research journals and a review journal: the Journal of Pharmacology and Experimental Therapeutics, Drug Metabolism and Disposition, Molecular Pharmacology, and Pharmacological Reviews Starting in 2012 these publications are only offered online. The society copublishes a wholly open access journal with the British Pharmacological Society and Wiley entitled Pharmacology Research & Perspectives. ASPET also publishes a quarterly newsletter, The Pharmacologist, and, from 2001 to 2011, Molecular Interventions magazine. The society gives out several awards:
It is synthesized from lathosterol by the enzyme lathosterol oxidase (lathosterol 5-desaturase). This is the next-to-last step of cholesterol biosynthesis. Defective synthesis results in the human inherited disorder lathosterolosis resembling Smith–Lemli–Opitz syndrome. Mice where this gene has been deleted lose the ability to increase vitamin D3 in the blood following UV exposure of the skin. The skin consists of two primary layers: an inner layer, the dermis, comprising largely connective tissue, and an outer, thinner epidermis. The thickness of the epidermis ranges from 0.04 mm to greater than 0.6 mm. The epidermis comprises five strata; from outer to inner, they are the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The highest concentrations of 7-dehydrocholesterol are found in the epidermal layer of skin—specifically in the stratum basale and stratum spinosum. The production of pre-vitamin D3 is, therefore, greatest in these two layers.
The inverted terminal repeat (ITR) sequences comprise 145 bases each. They were named so because of their symmetry, which was shown to be required for efficient multiplication of the AAV genome. The feature of these sequences that gives them this property is their ability to form a hairpin, which contributes to so-called self-priming that allows primase-independent synthesis of the second DNA strand. The ITRs were also shown to be required for both integration of the AAV DNA into the host cell genome (19th chromosome in humans) and rescue from it, as well as for efficient encapsidation of the AAV DNA combined with generation of a fully assembled, deoxyribonuclease-resistant AAV particles. With regard to gene therapy, ITRs seem to be the only sequences required in cis next to the therapeutic gene: structural (cap) and packaging (rep) proteins can be delivered in trans. With this assumption many methods were established for efficient production of recombinant AAV (rAAV) vectors containing a reporter or therapeutic gene. However, it was also published that the ITRs are not the only elements required in cis for the effective replication and encapsidation. A few research groups have identified a sequence designated cis-acting Rep-dependent element (CARE) inside the coding sequence of the rep gene. CARE was shown to augment the replication and encapsidation when present in cis.
Sources: en.wikipedia.org
Afucosylated antibodies are intensely used in the field of advanced medicine, also due to their high ADCC (antibody-dependent cellular cytotoxicity). This makes them effective in binding to specific targets while minimizing damage to surrounding tissue. Some of the fields in which afucosylated antibodies are used or considered for application are: cancer immunotherapy autoimmune diseases Infectious diseases Furthermore, afucosylated antibodies are used as diagnostic tools and play a role in the development of personalized medications.
Linked-read sequencing, a type of DNA sequencing technology, uses specialized technique that tags DNA molecules with unique barcodes before fragmenting them. Unlike traditional sequencing technology, where DNA is broken into small fragments and then sequenced individually, resulting in short read lengths that has difficulties in accurately reconstructing the original DNA sequence, the unique barcodes of linked-read sequencing allows scientists to link together DNA fragments that come from the same DNA molecule. A pivotal benefit of this technology lies in the small quantities of DNA required for large genome information output, effectively combining the advantages of long-read and short-read technologies.
Interpretation for secondary adrenal insufficiency In secondary adrenal insufficiency, due to exogenous steroid administration suppressing pituitary production of ACTH or due to primary pituitary disorder causing insufficient ACTH production, the adrenal glands will atrophy over time and cortisol production will fall and patients will fail stimulation testing. Early in the development of secondary adrenal insufficiency, the adrenals may not have atrophied and can still stimulate, resulting in a normal cosyntropin stimulation test. If secondary adrenal insufficiency is diagnosed, the insulin tolerance test (ITT) or the CRH (corticotropin-releasing hormone) stimulation test can be used to distinguish between a hypothalamic (tertiary) and pituitary (secondary) cause but is rarely used in clinical practice. Measuring a morning, fasting ACTH level helps assess for the etiology of adrenal insufficiency. Interpretation for primary adrenal insufficiency and Addison's disease ACTH will be high – usually well above upper limits of reference range.
The charged aerosol detector (CAD) is a detector used in conjunction with high-performance liquid chromatography (HPLC) and ultra high-performance liquid chromatography (UHPLC) to measure the amount of chemicals in a sample by creating charged aerosol particles which are detected using an electrometer. It is commonly used for the analysis of compounds that cannot be detected using traditional UV/Vis approaches due to their lack of a chromophore. The CAD can measure all non-volatile and many semi-volatile analytes including, but not limited to, antibiotics, excipients, ions, lipids, natural products, biofuels, sugars and surfactants. The CAD, like other aerosol detectors (e.g., evaporative light scattering detectors (ELSD) and condensation nucleation light scattering detectors (CNLSD)), falls under the category of destructive general-purpose detectors (see Chromatography detectors).
Based on its amino acid profile C-5 sterol desaturase appears to have four to five membrane-spanning regions, suggesting that it is a transmembrane protein. C5SD activity has been demonstrated in microsomes from rat tissue, implying that rat enzyme localizes to the endoplasmic reticulum Fluorescence microscopy experiments have shown that in the ciliate Tetrahymena thermophila C5SD localizes to the endoplasmic reticulum and that in S. cerevisiae C5SD localizes to both the endoplasmic reticulum and vesicles. In Arabidopsis thaliana C5SD is located in both the endoplasmic reticulum and lipid particles.
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.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。