A practical reference on peptidase cleavage: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-10-23. Anything still debated is marked as such rather than presented as settled.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
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。
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
=== 1973 to 2009 === Hanmi was founded in 1973 by Lim Sung-ki, who was a pharmacist. It was originally named Lim, Sung-ki Pharmaceutical Co., but it was quickly changed to Hanmi Pharmaceutical. The company originally started selling Trimethoprim/sulfamethoxazole powder, and would expand to produce Cephalosporin antibiotics in 1985 and injectable Ceftriaxone antibiotics in 1987. By 1988 the company was listed in the Korea Exchange. Hanmi started selling drugs in China in 1996. In 1994, the company began developing Cyclosporin. The company broke the ₩100,000,000,000 barrier in sales in 1997. The company began moving into the European market in 1998. The company still was developing new drugs, with Paclitaxel in 2000, Itraconazole tablets in 2001, 24-hour controlled-release Nifedipine tablets and a new salt form of Amlodipine in 2004, and an anti-obesity drug using sibutramine mesilate in 2007. Hanmi and Crystal Genomics formed a strategic partnership in 2008.
Smoking earlier in life and smoking cigarettes with higher tar content increases the risk of these diseases. Additionally, other forms of environmental tobacco smoke exposure, known as passive smoke and third-hand smoke, have manifested harmful health effects in people of all ages. Tobacco use is also a significant risk factor in miscarriages among pregnant women who smoke. It contributes to several other health problems for the fetus, such as premature birth and low birth weight, and increases the chance of sudden infant death syndrome (SIDS) by 1.4 to 3 times. The incidence of erectile dysfunction is approximately 85 percent higher in men who smoke compared to men who do not smoke. Many countries have taken measures to control tobacco consumption by restricting its usage and sales. They have printed warning messages on packaging. Moreover, smoking bans in public places like workplaces, theaters, bars, and restaurants have been enacted to reduce exposure to passive smoke. Tobacco taxation inflating the price of tobacco products, have also been imposed. In the late 1700s and the 1800s, the idea that tobacco use caused certain diseases, including mouth cancers, was initially accepted by the medical community. In the 1880s, automation dramatically reduced the cost of cigarettes, cigarette companies greatly increased their marketing, and use expanded. From the 1890s onwards, associations of tobacco use with cancers and vascular disease were regularly reported.
=== 17 March === Slovakia decided to provide Ukraine with 13 MiG-29 jets in varying states of readiness. The International Criminal Court issued an arrest warrant against Russian President Vladimir Putin and his Commissioner for Children's Rights Maria Lvova-Belova for allegations of war crimes during the war in Ukraine. Later in March, the Hungarian Prime Minister's chief of staff, Gergely Gulyás, said that Hungary would not arrest Putin if he entered the country, stating that the warrant was inconsistent with Hungarian law.
Currently, FDA have already approved a number of diagnostics assays utilizing microarrays: Agendia's MammaPrint assays can inform the breast cancer recurrence risk by profiling the expression of 70 genes related to breast cancer; Autogenomics INFNITI CYP2C19 assay can profile genetic polymorphisms, whose impacts on therapeutic response to antidepressants are great; and Affymetrix's CytoScan Dx can evaluate intellectual disabilities and congenital disorders by analyzing chromosomal mutation. In the future, the diagnostic tools for cancer will likely to focus on the Next Generation Sequencing (NGS). By utilizing DNA and RNA sequencing to do cancer diagnostics, technology in the field of molecular diagnostics tools will develop better. Although NGS throughput and price have dramatically been reduced over the past 10 years by roughly 100-fold, we remain at least 6 orders of magnitude away from performing deep sequencing at a whole genome level. Currently, Ion Torrent developed some NGS panels based on translational AmpliSeq, for example, the Oncomine Comprehensive Assay. They are focusing on utilizing deep sequencing of cancer-related genes to detect rare sequence variants. Molecular diagnostics tool can be used for cancer risk assessment. For example, the BRCA1/2 test by Myriad Genetics assesses women for lifetime risk of breast cancer. Also, some cancers are not always employed with clear symptoms. It is useful to analyze people when they do not show obvious symptoms and thus can detect cancer at early stages.
Sources: en.wikipedia.org
Opium (also known as poppy tears, or Lachryma papaveris) is the dried latex obtained from the seed capsules of the opium poppy Papaver somniferum. Approximately 12 percent of opium is made up of the analgesic alkaloid morphine, which is processed chemically to produce heroin and other synthetic opioids for medicinal use and for the illegal drug trade. Opium's main psychoactive alkaloids, primarily morphine, act on μ-opioid receptors, causing analgesia, with long-term use leading to tolerance and dependence. The latex also contains the closely related opiates codeine and thebaine, and non-analgesic alkaloids such as papaverine and noscapine. The traditional, labor-intensive method of obtaining the latex is to scratch ("score") the immature seed pods (fruits) by hand; The latex leaks out and dries to a sticky yellowish residue that is later scraped off and dehydrated. The English word for opium is borrowed from Latin, which in turn comes from Ancient Greek: ὄπιον (ópion), a diminutive of ὀπός (opós, 'juice of a plant'). The word meconium (derived from the Greek for "opium-like", but now used to refer to newborn stools) historically referred to related, weaker preparations made from other parts of the opium poppy or different species of poppies. The Mediterranean region holds the earliest archaeological evidence of human use of opium poppies dating back to before 5000 BCE, with cultivation beginning around 3400 BCE in Mesopotamia.
== Medical uses == Dexrazoxane has been used to protect the heart against the cardiotoxic side effects of chemotherapeutic drugs such as anthracyclines, such as daunorubicin or doxorubicin or other chemotherapeutic agents. However, in July 2011 the European Medicines Agency (EMA) released a statement restricting use only in adult patients with cancer who have received > 300 mg/m2 doxorubicin or > 540 mg/m2 epirubicin and general approval for use for cardioprotection. That showed a possibly higher rate of secondary malignancies and acute myelogenous leukemia in pediatric patients treated for different cancers with both dexrazoxane and other chemotherapeutic agents that are associated with secondary malignancies. On 19 July 2017, based on evaluation of the currently available data the European Commission issued an EU-wide legally binding decision to implement the recommendations of the Committee for Medicinal Products for Human Use (CHMP) on dexrazoxane and lifted its 2011-contraindication for primary prevention of anthracycline-induced cardiotoxicity with dexrazoxane in children and adolescents where high doses (≥ 300 mg/m3) of anthracyclines are anticipated. Dexrazoxane was designated by the US FDA as an orphan drug for "prevention of cardiomyopathy for children and adults 0 through 16 years of age treated with anthracyclines". This decision allows virtually all children to receive dexrazoxane starting with the first dose of anthracycline at the discretion of the treating provider.
Whey Protein: 96 Whole Soy Bean: 96 Human milk: 95 Chicken egg: 94 Soybean milk: 91 Buckwheat: 90+ Cow milk: 90 Cheese: 84 Quinoa: 83 Rice: 83 Defatted soy flour: 81 Fish: 76 Beef: 74 Immature bean: 65 Full-fat soy flour: 64 Soybean curd (tofu): 64 Whole wheat: 64 White flour: 41 Common foodstuffs and their values: (Note: These values use "whole egg" as a value of 100, so foodstuffs that provide even more nitrogen than whole eggs, can have a value of more than 100. 100, does not mean that 100% of the nitrogen in the food is incorporated into the body, and not excreted, as in other charts.)
Sources: en.wikipedia.org
== Further reading == Müller, Rainer H.; Mäder, Karsten; Gohla, Sven (3 July 2000). "Solid lipid nanoparticles (SLN) for controlled drug delivery – a review of the state of the art". European Journal of Pharmaceutics and Biopharmaceutics. 50 (1): 161–177. doi:10.1016/S0939-6411(00)00087-4. PMID 10840199. Shah, Mansi K.; Madan, Parshotam; Lin, Senshang (June 2014). "Preparation, in vitro evaluation and statistical optimization of carvedilol-loaded solid lipid nanoparticles for lymphatic absorption via oral administration". Pharmaceutical Development and Technology. 19 (4): 475–485. doi:10.3109/10837450.2013.795169. PMID 23697916. S2CID 42174732. Shah, Mansi K.; Madan, Parshotam; Lin, Senshang (3 October 2015). "Elucidation of intestinal absorption mechanism of carvedilol-loaded solid lipid nanoparticles using Caco-2 cell line as an in-vitro model". Pharmaceutical Development and Technology. 20 (7): 877–885. doi:10.3109/10837450.2014.938857. PMID 25069593. S2CID 40506806.
=== False eggs === Calculus: Calculi are egg-like objects formed in the stomachs of ruminants such as cattle, deer, elk, and goats. Calculus formation is a defense mechanism protecting the ruminant's stomach from damage if it swallows a foreign object while grazing. After ingestion, the object is covered by the same material composing bone, calcium phosphate, and eventually vomited out of the animal's system. These "stomach stones" tend to range in size from 1 to 6 centimeters. Larger sizes are known but very rare. Sometimes tiny dimples cover the surface of a stomach stone, which can fool observers into thinking they are the pores of an egg. Fossil egg expert Ken Carpenter has described stomach stones as the most egg-like natural objects, noting that they are "the trickiest [egg-like] objects to correctly identify". Calculi are so egg-like that on one occasion a detailed description of a stomach stone misidentified as a fossil egg was published in the scientific literature. Calculi can be distinguished from real egg fossils because when they are broken open, they show the layers of calcium phosphate and the foreign object at the core. Multiple layers of eggshell are known in pathological eggs, but these layers don't go all the way down to its core the way a stomach stone's do. Calculi are often suspiciously intact, unlike fossil eggs, which are usually damaged. Stomach stones also lack distinct shells with their attending structural components like continuous or prismatic layers, mammillae, and pores.
== Abstracting and indexing == Xenobiotica is abstracted and indexed in Biochemistry and Biophysics Citation Index, BIOSIS, Chemical Abstracts; Current Contents/Life Science, EBSCO, Science Citation Index, PASCAL, SciSearch, Scopus, and Index Medicus/MEDLINE/PubMed.
== Technology == Vaxess's business plan is based around a technology developed by Tufts University Professors Fiorenzo Omenetto and David Kaplan. The technology uses a silk-derived protein called fibroin to stabilize vaccines so that they can be shipped and stored without refrigeration, eliminating the need for the cold chain. Vaxess is working with vaccine manufacturers to develop heat-stable vaccines and targeting a product launch by 2019.
Sources: en.wikipedia.org
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.