Everything below concerns PTMA gene. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-04-19. Numbers and descriptions here follow the published literature rather than marketing material.
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。
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
| 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 |
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
Thymosin alpha 1 is a synthetic 28-amino-acid peptide first isolated in 1966 from thymosin fraction 5, a bovine thymus extract. Its chain begins with an acetylated serine residue and ends with asparagine. The native peptide carries a molecular mass near 3,108 daltons. Researchers classify it as an immunomodulatory agent rather than a hormone with a single endocrine target. Early work framed it as a thymus-derived factor that supports T-cell maturation. The synthetic form used in research and clinical products matches the natural sequence.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
===== Voter analysis ===== An Institute for Middle East Understanding (IMEU) poll conducted by YouGov from December 2024 to January 2025 found that the most important issues affecting the vote of Biden 2020 voters that did not vote for Harris were "Ending Israel's violence in Gaza" (29%), "The economy" (24%), followed by "Medicare and Social Security," (12%) "Immigration and border security," (11%) "Healthcare," (10%) and "Abortion" (9%). The survey found swing state Biden 2020 non-Harris voters ranked Gaza as less important than non-swing state voters. The survey also found that 36% of these voters would have been more likely to vote for Harris if she "had pledged to break from President Biden's policy toward Gaza by promising to withhold additional weapons to Israel for committing human rights abuses against Palestinian civilians."
=== EC 1.12.98 With other known acceptors === EC 1.12.98.1: coenzyme F420 hydrogenase EC 1.12.98.2: 5,10-methenyltetrahydromethanopterin hydrogenase EC 1.12.98.3: Methanosarcina-phenazine hydrogenase EC 1.12.98.4: Sulfhydrogenase
=== Shape and Morphology === The shape of the apical foramen exhibits considerable variation across different teeth. While standard instrumentation assumes a circular geometry, the foramen can present as oval, uneven, semilunar, or even flat. Recent studies have identified the round configuration as the most prevalent overall, with reported frequencies ranging from 57% to 65.1% of sampled teeth. Specifically, Manva et al. classified 65.1% of foramina as round and 31% as oval, with rare occurrences of uneven (2.7%), semilunar (0.6%), and flat (0.6%). The distribution of these shapes varies by tooth type; for instance, the round shape was most frequently observed in mandibular canines (77.8%), whereas the flat shape was exclusively evident in maxillary second molars. Despite the dominance of round shapes in these recent studies, significant controversies exist in the literature. Some researchers have reported round configuration prevalence as high as 94%, while others have found oval shapes to be the most common in posterior teeth, with prevalence rates reaching 71% to 81%. Swathika et al. noted that oval shapes were present in 56.7% of maxillary central incisors but found them to be less common in posterior teeth (27%) than previously thought. These morphological variations, particularly oval and irregular shapes, pose clinical challenges during root canal therapy if standard round instruments are used.
These time and length-scales can be used to understand the dependence of the conduction velocity on the diameter of the neuron in unmyelinated fibers. For example, the time-scale τ increases with both the membrane resistance rm and capacitance cm. As the capacitance increases, more charge must be transferred to produce a given transmembrane voltage (by the equation Q = CV); as the resistance increases, less charge is transferred per unit time, making the equilibration slower. In a similar manner, if the internal resistance per unit length ri is lower in one axon than in another (e.g., because the radius of the former is larger), the spatial decay length λ becomes longer and the conduction velocity of an action potential should increase. If the transmembrane resistance rm is increased, that lowers the average "leakage" current across the membrane, likewise causing λ to become longer, increasing the conduction velocity.
Sources: en.wikipedia.org
The identifying NPU codes may be used as identifiers with local terms, but a systematically shortened form of the NPU definition is available and is frequently used as a "name" in laboratory reports, for example:
=== Psychiatric disorders === Beta blockers have been researched for treatment of a variety of psychiatric disorders besides anxiety disorders. These include depression, mania, acute stress disorder, post-traumatic stress disorder (PTSD), schizophrenia, aggression, and agitation. Beta blockers have also been used for the treatment of schizoid personality disorder. However, there is limited evidence supporting the efficacy of supplemental beta blocker use in addition to antipsychotic drugs for treating schizophrenia.
== Adverse effects == The adverse-event profile of ceftolozane/tazobactam from two phase II trials (comparing either ceftolozane alone or in combination with tazobactam to ceftazidime or meropenem) suggests that ceftolozane/tazobactam is well tolerated. The most common adverse effects reported with ceftolozane/tazobactam are headache (5.8%), constipation (3.9%), hypertension (3%), nausea (2.8%), and diarrhea (1.9%).
Sulfur dioxygenase (EC 1.13.11.18, sulfur oxygenase, sulfur:oxygen oxidoreductase) is an enzyme with systematic name S-sulfanylglutathione:oxygen oxidoreductase. This enzyme catalyses the following chemical reaction
A media blackout was imposed, white civilians evacuated further south, public assembly rights revoked, and the security forces empowered to detain suspicious persons indefinitely. Police reinforcements were sent to the border, and in the ensuing crackdown they arrested 213 Ovambos. South Africa was sufficiently alarmed at the violence to deploy a large SADF contingent as well. They were joined by Portuguese troops who moved south from across the border to assist them. By the end of March order had been largely restored and most of the remaining strikers returned to work.
Sources: en.wikipedia.org
===== Sliding-rebinding model ===== The sliding-rebinding model differs from the allosteric model in that the allosteric model posits that only one binding site exists and can be altered, but the sliding-rebinding model states that multiple binding sites exist and aren't changed by EGF extension. Rather, in the bent conformation which is favored at low applied forces, the applied force is perpendicular to the line of possible binding sites. Thus, when the association between ligand and lectin domain is interrupted, the bond quickly dissociates. At larger applied forces, however, the protein is extended and the line of possible binding sites is aligned with the applied force, allowing the ligand to quickly re-associate with a new binding site after the initial interaction is disrupted. With multiple binding sites, and even the ability to re-associate with the original binding site, the rate of ligand dissociation would be decreased as is typical of catch bonds.
In a study published in 2010, researchers from Peking University studying ultrasound images of infants who fell ill in the 2008 contamination found while most children in a rural Chinese area recovered, 12 per cent still showed kidney abnormalities six months later. "The potential for long-term complications after exposure to melamine remains a serious concern", the report said. "Our results suggest a need for further follow-up of affected children to evaluate the possible long-term impact on health, including renal function."
==== Semisynthesis ==== The semisynthesis of steroids often begins from precursors such as cholesterol, phytosterols, or sapogenins. The efforts of Syntex, a company involved in the Mexican barbasco trade, used Dioscorea mexicana to produce the sapogenin diosgenin in the early days of the synthetic steroid pharmaceutical industry.
== Deficiencies and toxicity == An inadequate amount of a nutrient is a deficiency. Deficiencies can be due to several causes, including an inadequacy in nutrient intake, called a dietary deficiency, or any of several conditions that interfere with the utilization of a nutrient within an organism. Some of the conditions that can interfere with nutrient utilization include problems with nutrient absorption, substances that cause a greater-than-normal need for a nutrient, conditions that cause nutrient destruction, and conditions that cause greater nutrient excretion. Nutrient toxicity occurs when excess consumption of a nutrient does harm to an organism. In the United States and Canada, recommended dietary intake levels of essential nutrients are based on the minimum level that "will maintain a defined level of nutriture in an individual", a definition somewhat different from that used by the World Health Organization and Food and Agriculture Organization of a "basal requirement to indicate the level of intake needed to prevent pathologically relevant and clinically detectable signs of a dietary inadequacy". In setting human nutrient guidelines, government organizations do not necessarily agree on amounts needed to avoid deficiency or maximum amounts to avoid the risk of toxicity. For example, for vitamin C, recommended intakes range from 40 mg/day in India to 155 mg/day for the European Union. The table below shows U.S.
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。
Thymosin fraction 5 is a mixture of many peptides obtained from thymus tissue, while thymosin alpha 1 is a single defined 28-residue molecule. The two names appear together in older literature because the purified peptide was first obtained from that mixture.