The short version of 合成肽 fits in a sentence. The long version — which is the one that helps — is below.
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Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C129H215N33O55 | Calculated for the acetylated 28-residue peptide |
| Appearance | White to off-white powder | Lyophilized solid recovered from aqueous buffer |
| Solubility | Freely soluble in water | Typically dissolved in water or buffer before use |
| Typical storage | -20 C or below, desiccated | Protect from light and avoid repeated freeze-thaw cycles |
| Identity testing | Reverse-phase HPLC with mass spectrometry | Retention time and measured mass confirm the sequence |
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
Routine handling calls for storage of the lyophilized powder at refrigerated temperatures, away from light, in a sealed container. Working solutions are often prepared in sterile water or buffer and kept cold between uses. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation and loss of material. Laboratories usually record lot number, reconstitution date, and storage conditions so that any change in behavior can be traced to a specific preparation.
Reverse-phase high-performance liquid chromatography is the standard technique for assessing purity and concentration, because the peptide's hydrophobicity allows clean separation from related impurities. Mass spectrometry confirms molecular identity and detects sequence errors or truncations. Amino acid analysis and peptide mapping supply additional structural confirmation when required. Chromatographic purity values reported on certificates of analysis describe the proportion of the main peak and do not by themselves establish biological activity.
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。
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。
Identity and purity are normally assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities and truncation products. Mass spectrometry confirms molecular mass and detects modifications such as deamidation or oxidation. Amino acid analysis and peptide mapping provide additional sequence-level confirmation. For research material, a certificate of analysis typically reports these results together with water content and counter-ion identity, since the lyophilized powder is often supplied as an acetate or trifluoroacetate salt.
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
== Definition == Gynecomastia is the abnormal non-cancerous enlargement of one or both breasts in men due to the growth of breast tissue as a result of a hormone imbalance between estrogen and androgen. Gynecomastia is different from "pseudogynecomastia", which is defined as an excess of skin and/or adipose tissue in the male breasts without the growth of true glandular breast tissue; this is commonly associated with obesity and can be ruled out by physical exam.
=== Cardiomyopathies === Cardiomyopathies are generally inherited as autosomal dominants, although recessive forms have been described, and dilated cardiomyopathy can also be inherited in an X-linked pattern. Consequently, in addition to tragedy involving an athlete who succumbs, there are medical implications for close relatives. Among family members of index cases, more than 300 causative mutations have been identified. However, not all mutations have the same potential for severe outcomes, and there is not yet a clear understanding of how these mutations (which affect the same myosin protein molecule) can lead to the dramatically different clinical characteristics and outcomes associated with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Since HCM, as an example, is typically an autosomal dominant trait, each child of an HCM parent has a 50% chance of inheriting the mutation. In individuals without a family history, also known as sporadic cases, a common cause of the disease may be a "de novo" mutation of the gene that produces the β-myosin heavy chain, with two out of seven tested patients falling into this category.
=== Farming === About 70% of lotus for human consumption is produced in China. In 2005, the cultivation area in China was estimated at 300,000 hectares (740,000 acres). A majority of lotus production takes place in managed farming systems in ponds or flooded fields like rice. There three main ways of producing these flowers:
22 January to 18 March The U.S. 3rd Marine Division launched Operation Dewey Canyon to attack People's Army of Vietnam (PAVN) base areas in the A Shau and Song Đa Krông Valleys of Quảng Trị Province. The operation results in 1,617 PAVN killed while 130 Marines were killed.
Sources: en.wikipedia.org
=== Mass spectrometer === Quadrupole, magnetic sector, and time-of-flight (TOF) are the three mass spectrometers (MS) used in SIMS. For SSIMS, the primary requirement is low primary-ion flux density, which results in extremely low secondary ion yield (10−3 – 10−8 atoms/cm3). Hence, there is a need to collect almost all the secondary ions. High transmission (0.5–1) of TOF maximizes the sensitivity (104 times that of quadrupole MS). Parallel detection together with reasonable mass resolution and high mass range (m/z > 103) are among its other major advantages. Ions are accelerated to a given potential so that they have the same kinetic energy, resulting in ions of different mass:charge (m/e) ratio having different velocities. These ions then pass through a region of field-free space in the flight tube, and spread out in time, with the higher-mass ions arriving later at the end of the flight tube, where a time-sensitive detection system produces a mass spectrum. The primary ions are pulsed into short bursts of less than 10 ns (the time scale of secondary-ion emission after impact is negligible (<10−12 s)). The primary beam is pulsed by a rapid deflection across a small aperture or by off-axis deflection, followed by a curved magnetic field to compress the pulse in space. There are very high accelerating fields at the sample (high extraction voltage and small (mm) extraction gaps) to reduce the initial energy spread of the secondary ions. Some TOF systems further compensate for this energy spread by using nonlinear flight tubes.
Apicomplexans are a group of alveolates. Like the helicosproidia, they're parasitic, and have a nonphotosynthetic chloroplast. They were once thought to be related to the helicosproidia, but it is now known that the helicosproida are green algae rather than part of the CASH lineage. The apicomplexans include Plasmodium, the malaria parasite. Many apicomplexans keep a vestigial red algal derived chloroplast called an apicoplast, which they inherited from their ancestors. Apicoplasts have lost all photosynthetic function, and contain no photosynthetic pigments or true thylakoids. They are bounded by four membranes, but the membranes are not connected to the endoplasmic reticulum. Other apicomplexans like Cryptosporidium have lost the chloroplast completely. Apicomplexans store their energy in amylopectin granules that are located in their cytoplasm, even though they are nonphotosynthetic. The fact that apicomplexans still keep their nonphotosynthetic chloroplast around demonstrates how the chloroplast carries out important functions other than photosynthesis. Plant chloroplasts provide plant cells with many important things besides sugar, and apicoplasts are no different—they synthesize fatty acids, isopentenyl pyrophosphate, iron-sulfur clusters, and carry out part of the heme pathway. The most important apicoplast function is isopentenyl pyrophosphate synthesis—in fact, apicomplexans die when something interferes with this apicoplast function, and when apicomplexans are grown in an isopentenyl pyrophosphate-rich medium, they dump the organelle.
=== Candice Allbright === Candice Allbright (Alexandra Moen) is Eric's wife, with whom he has two daughters. She and Eric share a profane sense of humor. She later divorces Eric between series 2 and 3. In series 4, Candice and Eric learn that their daughter Lily has been expelled from school for catfishing another student; Candice blames Lily's behavioral issues on Eric's absence as a father. Eric lets Candice and Lily stay at the hotel suite serving as the office of SternTao, his hedge fund with Harper. Candice tells Eric not to "confuse regret with love."
Sources: en.wikipedia.org
== Description == The Wound Man illustrates various injuries that a person might receive through war, accident, or disease: cuts and bruises from multiple weapons, rashes and pustules, thorn scratches, and the bites of venomous animals. The figure also includes some schematic anatomical outlines of several organs within his unusual, transparent abdomen.
== Further reading == Brickell, C., Ed. Gardeners' Encyclopedia of Plants and Flowers. Dorling Kindersley. 1989. Toomey, M. and E. Leeds. An Illustrated Encyclopedia of Clematis. Charles Chesshire (Timber Press). Ruth Gooch Clematis: The Complete Guide. Crowood Press 2001. Ruth & Jon Gooch Clematis An Essential Guide Crowood Press 2011.
=== General === Engdahl K., Ahlberg P. (1977). Journal of Chemical Research: 340–341. {{cite journal}}: Missing or empty |title= (help) Bensaude O, Chevrier M, Dubois J (1978). "Lactim-Lactam Tautomeric Equilibrium of 2-Hydroxypyridines. 1.Cation Binding, Dimerization and Interconversion Mechanism in Aprotic Solvents. A Spectroscopic and Temperature-Jump Kinetic Study". J. Am. Chem. Soc. 100 (22): 7055–7066. Bibcode:1978JAChS.100.7055B. doi:10.1021/ja00490a046. Bensaude O, Dreyfus G, Dodin G, Dubois J (1977). "Intramolecular Nondissociative Proton Transfer in Aqueous Solutions of Tautomeric Heterocycles: a Temperature-Jump Kinetic Study". J. Am. Chem. Soc. 99 (13): 4438–4446. Bibcode:1977JAChS..99.4438B. doi:10.1021/ja00455a037. Bensaude O, Chevrier M, Dubois J (1978). "Influence of Hydration upon Tautomeric Equilibrium". Tetrahedron Lett. 19 (25): 2221–2224. doi:10.1016/S0040-4039(01)86850-7. Hammes GG, Park AC (1969). "Kinetic and Thermodynamic Studies of Hydrogen Bonding". J. Am. Chem. Soc. 91 (4): 956–961. Bibcode:1969JAChS..91..956H. doi:10.1021/ja01032a028. Hammes GG, Spivey HO (1966). "A Kinetic Study of the Hydrogen-Bond Dimerization of 2-Pyridone". J. Am. Chem. Soc. 88 (8): 1621–1625. Bibcode:1966JAChS..88.1621H. doi:10.1021/ja00960a006. PMID 5942979. Beak P, Covington JB, Smith SG (1976). "Structural Studies of Tautomeric Systems: the Importance of Association for 2-Hydroxypyridine-2-Pyridone and 2-Mercaptopyridine-2-Thiopyridone". J. Am. Chem. Soc. 98 (25): 8284–8286. Bibcode:1976JAChS..98.8284B. doi:10.1021/ja00441a079. Beak P, Covington JB, White JM (1980).
Sources: en.wikipedia.org
It is a 28-amino-acid peptide originally purified from a bovine thymic extract and later produced synthetically. It is studied mainly for its effects on immune cell function.
No. The two peptides share part of a name but differ in length, sequence, and net charge. Literature searches that treat them as one compound return misleading results.
Solid-phase peptide synthesis is the usual route, and recombinant expression has also been described. Both approaches produce material matching the natural sequence.
It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.