reverse-phase HPLC 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 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
20世纪70年代，研究者从胸腺提取物中纯化出多种小肽，Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤，产量低且成分复杂。随着固相肽合成技术成熟，实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上，并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
Identity and purity are usually checked by reverse-phase high-performance liquid chromatography, which separates the intact chain from truncated products, together with mass spectrometry for confirmation of the expected mass. Peptide mapping after enzymatic digestion and amino acid analysis add sequence-level evidence. Release testing also covers water content, residual solvents, and counter-ions, all of which influence measured mass and stability. Related-peptide limits are commonly expressed as a percentage of total peak area, with individual unspecified impurities held below a lower threshold.
The lyophilized peptide is a white to off-white powder that dissolves freely in water and in aqueous buffers near neutral pH. Because the molecule carries a net negative charge under physiological conditions, saline and phosphate solutions are the usual vehicles, while strongly acidic media are avoided. Stock solutions are commonly divided into small aliquots so that repeated freezing and thawing can be limited, since cycling may encourage aggregation. Solubility in organic solvents is poor and those solvents are seldom used as primary diluents.
| Property | Value | Notes |
|---|---|---|
| 化学分类 | 线性肽 | 由28个氨基酸组成 |
| 分子量 | 约3108 Da | 合成版本一致 |
| 外观 | 白色至类白色粉末 | 冻干品 |
| 溶解度 | 易溶于水 | 微溶于有机溶剂 |
| 储存温度 | -20°C（冻干） | 溶解后2-8°C |
On the other hand, a mutation may occur in a somatic cell of an organism. Such mutations will be present in all descendants of this cell within the same organism. The accumulation of certain mutations over generations of somatic cells is part of cause of malignant transformation, from normal cell to cancer cell. Cells with heterozygous loss-of-function mutations (one good copy of gene and one mutated copy) may function normally with the unmutated copy until the good copy has been spontaneously somatically mutated. This kind of mutation happens often in living organisms, but it is difficult to measure the rate. Measuring this rate is important in predicting the rate at which people may develop cancer. Point mutations may arise from spontaneous mutations that occur during DNA replication. The rate of mutation may be increased by mutagens. Mutagens can be physical, such as radiation from UV rays, X-rays or extreme heat, or chemical (molecules that misplace base pairs or disrupt the helical shape of DNA). Mutagens associated with cancers are often studied to learn about cancer and its prevention.
=== Polymer chemistry === Although MS-based analyses of polymers have largely been performed using single-stage MS, tandem MS has also been used to characterize polymer components. CID is the most common method of dissociation used, but ETD has been used as a complementary method. Unique bond cleavages resulting from ETD supply valuable diagnostic information.
Das RC, Heath EC (1980). "Dolichyldiphosphoryloligosaccharide--protein oligosaccharyltransferase; solubilization, purification, and properties". Proc. Natl. Acad. Sci. U.S.A. 77 (7): 3811–5. Bibcode:1980PNAS...77.3811D. doi:10.1073/pnas.77.7.3811. PMC 349716. PMID 6933437.
=== Electrodiagnostic testing === Electromyography (EMG) and nerve conduction studies help distinguish myopathic from neurogenic causes of weakness and may show characteristic myopathic motor unit potentials or myotonic discharges. A myopathic EMG combined with proximal weakness and hyperCKemia substantially increases the likelihood of a positive muscle biopsy, although a normal EMG does not exclude myopathy.
BASF SE (German pronunciation: [beːaːɛsˈʔɛf] ), an initialism of its original name Badische Anilin- & Soda-Fabrik (German for 'Baden Aniline & Soda Factory'), is a German multinational company and the largest chemical producer in the world. Its headquarters is located in Ludwigshafen, Germany. BASF comprises subsidiaries and joint ventures in more than 80 countries, operating six integrated production sites and 390 other production sites across Europe, Asia, Australia, the Americas and Africa. BASF has customers in over 190 countries and supplies products to a wide variety of industries. Despite its size and global presence, BASF has received relatively little public attention since it abandoned the manufacture and sale of BASF-branded consumer electronics products in the 1990s. The company began as a dye manufacturer in 1865. Fritz Haber worked with Carl Bosch, one of its employees, to invent the Haber-Bosch process by 1912, after which the company grew rapidly. In 1925, the company merged with several other German chemical companies to become the chemicals conglomerate IG Farben. IG Farben would go on to play a major role in the economy of Nazi Germany. It extensively employed forced and slave labor during the Nazi period, and produced the notorious Zyklon B chemical used in the Holocaust. IG Farben was disestablished by the Allies in 1945. BASF was reconstituted from the remnants of IG Farben in 1952. It was part of the German economic miracle, and has since expanded considerably. It has received modern criticism for its poor environmental record.
Sources: en.wikipedia.org
Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. Moreover, nearly all commercially produced industrial enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, as is the case for single-cell proteins, baker's yeast, and starter cultures for lactic acid bacteria used in cheesemaking. In general, fermentations can be divided into four types:
December 13: Constitution of 22 Frimaire Year VIII (establishing the Consulate) grants citizenship only to men over 21, born and residing in France, and registered in their commune's civic registry, effectively excluding women. 1800
By inhibiting this pathway, less collagen was produced and deposited in the heart, preventing the formation of cardiac fibrosis. Huang and Chen (2013) claim that oxymatrine may even be involved in inhibiting the expression of TGF-β1 receptors, which would further support that oxymatrine attenuates the signal transduction pathway involved in collagen production. They also reported that inhibition of the TGF-β1 receptor may also prevent ventricular remodeling.
== Clinical significance == The CendR pathway is used to enhance transport of coupled and co-administered anti-cancer drugs into tumors. Tumor penetrating peptides (TPP, a class of tumor homing peptides containing a cryptic CendR motif) activate tumor specific transport through a three-step process that involves binding to a primary tumor-specific receptor, a proteolytic activation of CendR element, and binding to NRP-1 to activate the trans-tissue transport pathway. Clinical-stage prototypic CendR peptide iRGD, developed by Lisata Therapeutics as LSTA1, is utilized to make solid tumors temporarily more accessible to circulating anti-cancer drugs to increase their therapeutic index. Several viruses, including the SARS-CoV2 coronavirus, are also using the CendR system for cellular entry and tissue penetration, and it is known that viruses that have the system are more virulent and deadly.
Sources: en.wikipedia.org
=== Fermented dry sausage === Adding sake kasu when mixing the ingredients for fermented dry sausage can increase the speed of decomposition in both sarcoplasmic and myofibrillar proteins. It also can increase the amount of peptides and free amino acids, causing the fermented dry sausage to increase in hardness and acidity.
== Causes == The cause of IBM is unknown. IBM likely results from the interaction of a number of genetic and environmental factors. There are two major theories about how sIBM is caused. One hypothesis suggests that the inflammation-immune reaction, caused by an unknown trigger – likely an undiscovered virus or an autoimmune disorder – is the primary cause of sIBM and that the degeneration of muscle fibers and protein abnormalities are secondary features. Despite the arguments "in favor of an adaptive immune response in sIBM, a purely autoimmune hypothesis for sIBM is untenable because of the disease's resistance to most immunotherapy." The second school of thought advocates the theory that sIBM is a degenerative disorder related to aging of the muscle fibers and that abnormal, potentially pathogenic protein accumulations in myofibrils play a key causative role in sIBM (apparently before the immune system comes into play). This hypothesis emphasizes the abnormal intracellular accumulation of many proteins, protein aggregation and misfolding, proteosome inhibition, and endoplasmic reticulum (ER) stress. One review discusses the "limitations in the beta-amyloid-mediated theory of IBM myofiber injury." Dalakas (2006) suggested that a chain of events causes IBM – some sort of virus, likely a retrovirus, triggers the cloning of T cells. These T cells appear to be driven by specific antigens to invade muscle fibers.
== History == In 1980 Ferguson-Miller et al. at Michigan State developed n-dodecyl-β-D-maltopyranoside (DDM) as part of a successful effort to purify an active, stable, monodisperse form of cytochrome c oxidase. Maltosides have been used extensively to stabilize membrane proteins for biophysical and structural studies.
=== Military rule years === With this new orientation, the PCB grew in size and exercised a much greater role in the Brazilian left. However, the alliance forged with the other parties did not survive the 1964 Brazilian coup d'état. PCB did play an important role against the dictatorship, by organizing the workers movement and participating in efforts to unite the opposition in its demands for democratic reforms. At that point in time the communists were a fraction of the democratic opposition front, the Brazilian Democratic Movement (MDB). It refused, for example, to engage in armed struggle, differently from other left wing organizations that decided to follow that path. The clandestine operations and the political disputes regarding the strategies to resist the military regime led to many important leaders leaving the party, while many others died in the hands of the military regime. To the end of the dictatorship, while the Communist Party in Brazil was involved in several internal clashes, the Worker's Party (Partido dos Trabalhadores) was founded. Its creation was the project of a series of left wing groups independent from the PCB (Trotskyists, communist dissidents, ex-guerrillas, sectors of the Catholic Left, independent unionists and intellectuals). It was structured as an alternative to Communist-led unionism in Brazil. Forswearing the Popular Front strategy adopted by the PCB, the PT chose instead to take a more radical stance against the military regime and gained a strong presence in between high skilled workers and middle-class intellectuals.
=== Streptococcal TSS === Severe localized pain is typically the earliest and most prominent symptom. Common early stage symptoms include an influenza-like illness with fever, sore throat, and gastrointestinal upset. Up to fifty percent of cases have no identifiable site of bacterial entry, although soft-tissue infections are a common source. Unlike staphylococcal TSS, blood cultures are positive in 60 to 80 percent of streptococcal TSS cases. A scarlatiniform rash may be present but occurs less commonly than the erythroderma characteristic of staphylococcal disease.
Sources: en.wikipedia.org
它不是经典的内分泌激素，而是一种免疫调节肽。其作用主要通过局部免疫细胞间的信号传递实现，而非经血液循环作用于远隔器官。
天然胸腺素α1主要从胸腺组织提取，也可在脾脏和淋巴结中检出。目前研究和临床使用的多为化学合成版本，不再依赖动物组织。
胸腺素组分5是牛胸腺提取物的粗组分，包含多种肽。胸腺素α1是其中一种被纯化和表征的单一肽，具有明确的28个氨基酸序列。
Reconstituted solutions are typically kept refrigerated at two to eight degrees Celsius when used within a short window, or frozen in aliquots for longer periods. Repeated freeze-thaw cycles are avoided because they can reduce recovery of intact peptide.