If you have been reading about 反相色谱 and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-12-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
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.
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
Franz Joseph was born on 18 August 1830 in the Schönbrunn Palace in Vienna (on the 65th anniversary of the death of Francis of Lorraine) as the eldest son of Archduke Franz Karl (the younger son of Francis I), and Sophie, Princess of Bavaria. Because his uncle, reigning from 1835 as the Emperor Ferdinand, was disabled by seizures, and his father unambitious and retiring, the mother of the young Archduke "Franzi" brought him up as a future emperor, with emphasis on devotion, responsibility and diligence. For this reason, Franz Joseph was consistently built up as a potential successor to the imperial throne by his politically ambitious mother from early childhood. Up to the age of 7, little "Franzi" was brought up in the care of the nanny ("Aja") Louise von Sturmfeder. Then the "state education" began, the central contents of which were "sense of duty", religiosity and dynastic awareness. The theologian Joseph Othmar von Rauscher conveyed to him the inviolable understanding of rulership of divine origin (divine grace), and therefore a belief that no participation of the population in rulership in the form of parliaments was required. The educators Heinrich Franz von Bombelles and Colonel Johann Baptist Coronini-Cronberg ordered Archduke Franz to study an enormous amount of time, which initially comprised 18 hours per week and was expanded to 50 hours per week by the age of 16.
Alzheimer's disease (AD) is a neurodegenerative disease and is the most common cause of dementia, accounting for around 60–70% of cases. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems with language, disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. The median life expectancy following diagnosis of dementia is three to twelve years. Co-occurring movement disorder, also known as extrapyramidal signs, multiplies risk of death by 1.6. The causes of Alzheimer's disease remain poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an allele of apolipoprotein E, a protein involved in the metabolism of fats in mammals. Other risk factors include a history of head injury, clinical depression, and high blood pressure. The progression of the disease is largely characterised by the accumulation of malformed protein deposits in the cerebral cortex, called amyloid plaques and neurofibrillary tangles. These misfolded protein aggregates interfere with normal cell function, and over time lead to irreversible degeneration of neurons and loss of synaptic connections in the brain.
== Prognosis == The prognosis is generally poor with survival typically measured in months. The median survival time of patients without treatment is four to six weeks. The best prognoses are seen from NM due to breast cancer with the median overall survival of no more than six months after diagnosis of NM. Death is generally due to progressive neurological dysfunction. Treatment is meant to stabilize neurological function and prolong survival. Neurological dysfunction usually cannot be fixed but progressive dysfunction can be halted and survival may be increased to four to six months. It occurs in approximately 3-5% of cancer patients. The disease is usually terminal and if left untreated, the median survival is 4–6 weeks whereas if treated, the median survival can increase to 2–3 months. Treatment will be more effective if it is done on the primary tumor before it metastasizes to the brain or spinal cord. Patients with leukaemia achieve better results compared to patients with solid tumours who have undergone treatment. It was found that 75% of patients stabilize or improve over several months as opposed to 25% of patients who do not respond and have progressive disease. But despite initial improvement, most patients survive only a few months. Breast cancer and small cell lung cancer are the two solid tumors that respond best to treatment Some patients do better than others, particularly those whose primary cancer is hematologic, bone marrow and lymph nodes.
=== Genetics === In MCTD, major histocompatibility complex (MHC) and non-MHC genes have been linked to disease vulnerability. HLA-DR4 in the MHC is linked to both anti-RNP antibody responses and MCTD. The HLA class II phenotype/genotype most closely connected with scleroderma, HLA-DR5, and its subgroups, has been demonstrated to have a negative connection with MCTD. Another genetic feature of MCTD is the presence of anti-RNP antibodies. However, these antibodies are not present in all patients. Genome-wide association studies have revealed that there are parts of a patient’s genetic material that cause production of these anti-RNP antibodies. The mechanism is not yet thoroughly defined.
Sources: en.wikipedia.org
== Identification of Secondary Structure == VADAR identifies and assigns protein secondary structure using 3 different algorithms. These three methods are then combined to create a consensus secondary structure assignment. Only 3 types of secondary structure are identified: Helices are indicated with an "H", beta-strands are indicated with a "B" and coil or unstructured regions are identified with a "C". Secondary structure assignments for each residue are listed under the column labeled SCND STRUC. The first secondary structure identification method (which appears in column 1) uses a geometric masking approach that was first described by Richards and Kundrot with slight modifications. The second method (which appears in column 2) uses backbone dihedral angles to identify secondary structure elements in a manner initially described by Levitt and Greer as well as Chou and Fasman. The third secondary structure identification method uses hydrogen bonding patterns (in association with measured dihedral angles) to identify helices, beta strands and coil regions. This third method is somewhat similar to the method originally described by Kabsch and Sander. The net result or consensus secondary structure is a weighted combination of each of the three methods. VADAR’s method of secondary structure identification generally identifies a higher fraction of secondary structure elements than the DSSP algorithm (64% helices and beta strands for VADAR versus 51% helices and beta strands for DSSP).
Barry Windsor-Smith, who had come to prominence illustrating Marvel's Conan the Barbarian series, collaborated with Claremont for the "Wounded Wolf" story that was published as Uncanny X-Men #205 (May 1986), focusing entirely on Wolverine. The story introduced a new adversary for Wolverine, Lady Deathstrike. The "Mutant Massacre" story arc of 1986 brought Sabretooth into conflict with the X-Men and particularly Wolverine. Byrne had previously designed Sabretooth as an enemy of the martial artist superhero Iron Fist in Iron Fist #14 (August 1977), written by Claremont. Sabretooth's face was based on a preliminary and unused drawing Byrne had proposed for Wolverine; he became Wolverine's archenemy. Marvel launched an ongoing Wolverine title written by Claremont with art by John Buscema in November 1988. In the late 1980s, Wolverine featured in self-contained crossover stories with two other characters: Spider-Man, in Spider-Man versus Wolverine (1987), by Christopher Priest and M.D. Bright, and Nick Fury, in Wolverine/Nick Fury: The Scorpio Connection (1989), written by Archie Goodwin with art by Howard Chaykin.
==== Actions ==== The 2C drugs act as agonists of the serotonin 5-HT2 receptors, including of the serotonin 5-HT2A, 5-HT2B, and 5-HT2C receptors. They are partial agonists of the serotonin 5-HT2A receptor. Most of the 2C drugs have much lower affinity for the serotonin 5-HT1A receptor than for the serotonin 5-HT2A receptor. Most of the 2C drugs have also shown about 5- to 15-fold higher affinity for the serotonin 5-HT2A receptor over the serotonin 5-HT2C receptor and about 15- to 100-fold higher affinity for the serotonin 5-HT2A receptor over the serotonin 5-HT1A receptor. The psychedelic effects of the 2C drugs are thought to be mediated specifically by activation of the serotonin 5-HT2A receptor. Unlike many other phenethylamines, 2C drugs, including 2C-C, 2C-D, 2C-E, 2C-I, and 2C-T-2 among others, are inactive as monoamine releasing agents and reuptake inhibitors. Most of the 2C drugs are agonists of the rat and mouse trace amine-associated receptor 1 (TAAR1). However, most are inactive as agonists of the human TAAR1. The 2C drugs show very weak monoamine oxidase inhibition, including of monoamine oxidase A (MAO-A) and/or monoamine oxidase B (MAO-B).
==== Breast surgery ==== Breastfeeding can generally be attempted after breast augmentation or reduction surgery; however, prior breast surgery is a risk factor for low milk supply. A 2014 review found that women who have breast implant surgery were less likely to breastfeed exclusively; however, it was based on only three small studies, and the reasons for the correlation were not clear. A large follow-up study done in 2014 found a reduced rate of breastfeeding in women who had undergone breast augmentation surgery; however, again, the reasons were unclear. The authors suggested that women contemplating augmentation should be provided with information related to the rates of successful breastfeeding as part of informed decision-making when contemplating surgery. Prior breast reduction surgery is strongly associated with an increased probability of low milk supply due to disruption to tissues and nerves. Some surgical techniques for breast reduction appear to be more successful than others in preserving the tissues that generate and channel milk to the nipple. A 2017 review found that women were more likely to have success with breastfeeding with these techniques.
== Peroxisomal beta-oxidation == Fatty acid oxidation also occurs in peroxisomes when the fatty acid chains are too long to be processed by the mitochondria. The same enzymes are used in peroxisomes as in the mitochondrial matrix and acetyl-CoA is generated. Very long chain (greater than C-22) fatty acids, branched fatty acids, some prostaglandins and leukotrienes undergo initial oxidation in peroxisomes until octanoyl-CoA is formed, at which point it undergoes mitochondrial oxidation. One significant difference is that oxidation in peroxisomes is not coupled to ATP synthesis. Instead, the high-potential electrons are transferred to O2, which yields hydrogen peroxide. The enzyme catalase, found primarily in peroxisomes and the cytosol of erythrocytes (and sometimes in mitochondria), converts the hydrogen peroxide into water and oxygen. Peroxisomal β-oxidation also requires enzymes specific to the peroxisome and to very long fatty acids. There are four key differences between the enzymes used for mitochondrial and peroxisomal β-oxidation:
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.