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Last reviewed on 2025-11-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Amino acid length | 28 residues | Single chain with an acetylated N-terminus |
| Molecular mass | Approximately 3,108 Da | Small shifts occur with counter-ion and water content |
| Isoelectric point | Around 3.5 | Low value follows from the many acidic residues |
| Parent molecule | N-terminal region of prothymosin alpha | Free circulating form in humans is not firmly established |
| Common synonyms | Thymalfasin; T alpha 1 | Older literature also uses the full spelled-out form |
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Thymosin alpha 1 is a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.
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.
CCL7 is a multipotent chemokine involved in anti-bacterial, anti-viral and anti-fungal immune responses. For example, CCL7-mediated stimulation of CCR2 chemokine receptors on monocytes is participating in the elimination of Listeria monocytogenes infections by the recruitment of monocytes and TNF/iNOS-producing dendritic cells (TipDCs). Next, the role of the CCL7 was also observed in the mouse infected by West Nile Virus. The genetically deficient mice in CCL7 have increased mortality because of decrease in monocytes and neutrophils. Early induction of CCL7 downstream of TLR9 signaling also promotes the development of robust immunity to cryptococcal infections. Diseases associated with CCL7 dysregulation are observed. For example, an abnormal increase of CCL7 worsens many disorders, like HIV or lesional psoriasis. Furthermore, CCL7 is implicated in various immunological diseases, as ulcerative colitis, multiple sclerosis or nonatopic and atopic asthma. It seems, that the expression of CCL7 can activate an antitumor immune response.
Ethylhexyl palmitate, also known as octyl palmitate, is the fatty acid ester derived from 2-ethylhexanol and palmitic acid. It is frequently utilized in cosmetic formulations. Ethylhexyl palmitate is a branched saturated fatty ester derived from ethylhexyl alcohol and palmitic acid. Ethylhexyl palmitate is a clear, colorless liquid with a slightly fatty odor at room temperature. The ester is synthesized by reacting palmitic acid and 2-ethylhexanol in the presence of an acid catalyst. Ethylhexyl palmitate is used in cosmetic formulations as a solvent, carrying agent, pigment wetting agent, fragrance fixative and emollient. Its dry-slip skinfeel is similar to some silicone derivatives.
Outbreaks of disease Food-born illness Bioterrorism Natural disasters APHL plays a critical role in crisis response to these public health emergencies through the Laboratory Response Network (LRN). The LRN was formed in 1999 in a cooperative effort between APHL, the CDC and FBI to rapidly detect, and respond to public health emergencies. The Department of Defense has joined in the effort to support biological response activities. In addition to their leadership during times of crisis, APHL has a strong focus on preparing public health laboratories on how to respond to emergencies when they happen through training and capacity-building, as well as creating model frameworks that labs around the country can use in order to have procedures in place to handle a crisis when it happens.
Transcriptional gene regulation process depends on many spatial and temporal factors in the nucleus such as global or local chromatin states, nucleosome positioning, TF binding, enhancer/promoter activities. Variant that alter the function of any of these biological processes may alter the gene regulation and cause phenotypic abnormality. Genetic variants that located in distal regulatory region can affect the binding motif of TFs, chromatin regulators and other distal transcriptional factors, which disturb the interaction between enhancer/silencer and its target gene.
ACC Synthase is 450-516 amino acid long sequence depending on the species of plant from which it is extracted. Though it is comparable in the species in which it is found, its COOH-terminal domain is more variable, leading to differences such as oligomerization. The COOH-terminal domain is responsible for oligomerization. In most ACC Synthase producing cells, ACC Synthase exists as a dimer. However, in some we find a monomer ("which is more active and efficient [than its dimer counterpart"). The structure of ACS has been largely determined via X-ray crystallography. Conservation of the residues in ACS's catalytic domain and sequence homology suggest that ACS catalyzes the synthesis of ACC in a similar fashion as other enzymes that require PLP as a cofactor. However, unlike many other PLP-dependent enzymes, Lys (278) is not the only residue that interacts with the substrate. The proximity of the electronegative oxygen from Tyr (152) to the C-γ-S bond suggests a crucial role in the formation of ACC. X-ray crystallography with aminoethoxyvinylglycine (AVG) a competitive inhibitor confirmed Tyrosine's role in the γ elimination. As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1B8G, PDB: 1IAX, PDB: 1IAY, PDB: 1M4N, PDB: 1M7Y, and PDB: 1YNU.
Sources: en.wikipedia.org
Because protein chains are open, AlphaKnot uses closure procedures before applying knot invariants. Its probabilistic method repeatedly closes the chain using randomly selected points on a large surrounding sphere and assigns the dominant topology obtained from the ensemble of closures. Deterministic alternatives connect the chain termini using prescribed geometries, including a direct closure and a closure constructed using the centre of mass. Knot identification uses the HOMFLY polynomial to distinguish knot types. AlphaKnot recognizes knots with minimal representations containing up to 12 crossings. In large-scale database calculations, structures that exhibit evidence of a nontrivial knot are subsequently analysed to determine the corresponding knot core, the smallest portion of the protein chain required to retain the detected topology. The database primarily reports the topology of the complete protein chain. More detailed information about subchain topologies can be obtained by calculating a knot map, which records the topology of different portions of the sequence. Because producing full knot maps for hundreds of thousands of structures would require substantial computational resources, these calculations are performed on demand rather than precomputed for the entire AlphaFold DB v4 dataset.
First, a cell lysate is generated by glass beads beating, pressure homogenisation or chemical or physical lysis methods that do not denature the protein(s) of interest. (Optionally for targeted analysis) a protein of interest is purified out of this lysate by affinity methods based on intrinsically disordered tags or other suitable purification strategies, often involving several orthogonal chromatographic steps. This (total or purified) protein solution is aliquoted into several tubes of a PCR strip. All aliquots are exposed in parallel in a thermal gradient PCR cycler to different maximal temperatures in presence of the thermostable protease thermolysin (see figure). Automated temperature control is achieved in a thermal gradient cycler (commonly used for PCRs). Reaction products can be separated by SDS-PAGE or western blot. The protease thermolysin can be fully inactivated by EDTA. This feature of thermolysin makes FASTpp compatible with subsequent trypsin digestion e.g. for mass spectrometry.
Leukolike vectors are a type of nanoparticles made of nanoporous silicon encapsulated by extracted native leukocyte membranes. These particles were among the first artificial white blood cells to be studied as a proof of concept of using cellular membranes to prolong circulation of nanoparticles throughout the blood. Studies have shown that leukolike vectors have a specific advantage in chemotherapy drug delivery to cancer. This is because leukolike vectors specifically have the potential to bind to tumor endothelium.
Seven genes encode seven distinct 14-3-3 proteins in most mammals (See Human genes below) and 13–15 genes in many higher plants, though typically in fungi they are present only in pairs. Protists have at least one. Eukaryotes can tolerate the loss of a single 14-3-3 gene if multiple genes are expressed, but deletion of all 14-3-3s (as experimentally determined in yeast) results in death. 14-3-3 proteins are structurally similar to the Tetratrico Peptide Repeat (TPR) superfamily, which generally have 9 or 10 alpha helices, and usually form homo- and/or hetero-dimer interactions along their amino-termini helices. These proteins contain a number of known common modification domains, including regions for divalent cation interaction, phosphorylation & acetylation, and proteolytic cleavage, among others established and predicted. 14-3-3 binds to peptides. There are common recognition motifs for 14-3-3 proteins that contain a phosphorylated serine or threonine residue, although binding to non-phosphorylated ligands has also been reported. This interaction occurs along a so-called binding groove or cleft that is amphipathic in nature. To date, the crystal structures of six classes of these proteins have been resolved and deposited in the public domain.
Sources: en.wikipedia.org
φ29’s DNA packaging system, using pRNA, incorporates a motor for the delivery of therapeutic molecules like ribozymes and aptamers. The small size of pRNA-derived nanoparticles also helps to deliver drugs in tight spaces like blood vessels. The main difficulty in using aptamer-based drug delivery is sourcing unique aptamers and other multimers for specific treatments for diseases that potentially degrade therapeutic multimers and nanoparticles in vivo. Nanoparticles need to be stabilized as delivery mechanisms in order to adapt to microenvironments that may result in loss of therapeutic cargo.
The full-length human protein comprises 2,843 amino acids with a (predicted) molecular mass of 311646 Da. Several N-terminal domains have been structurally elucidated in unique atomistic high-resolution complex structures. Most of the protein is predicted to be intrinsically disordered. It is not known if this large predicted unstructured region from amino acid 800 to 2843 persists in vivo or would form stabilised complexes – possibly with yet unidentified interacting proteins. Recently, it has been experimentally confirmed that the mutation cluster region around the center of APC is intrinsically disordered in vitro.
A sequence space is usually laid out as a grid. For protein sequence spaces, each residue in the protein is represented by a dimension with 20 possible positions along that axis corresponding to the possible amino acids. Hence there are 400 possible dipeptides arranged in a 20x20 space but that expands to 10130 for even a small protein of 100 amino acids arranged in a space with 100 dimensions. Although such overwhelming multidimensionality cannot be visualised or represented diagrammatically, it provides a useful abstract model to think about the range of proteins and evolution from one sequence to another. These highly multidimensional spaces can be compressed to 2 or 3 dimensions using principal component analysis. A fitness landscape is simply a sequence space with an extra vertical axis of fitness added for each sequence.
Sources: en.wikipedia.org
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.
Prothymosin alpha is a much larger acidic protein, roughly 111 to 113 residues long, and the thymosin alpha-1 sequence matches its N-terminal region. The small peptide is therefore best understood as a fragment of that parent protein rather than a separate gene product.
Trials and clinical reports have examined chronic hepatitis B and C, use as a vaccine adjuvant, and supportive treatment in some immunodeficiency and oncology settings. Results vary by indication, and regulatory approval differs between countries.
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。