If you have been reading about actin binding and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-03-16. Numbers and descriptions here follow the published literature rather than marketing material.
Proposed activity centers on actin sequestration and on the movement of cells during repair processes. In cell culture and animal models, the fragment has been associated with migration, tube formation, and tissue remodeling. These observations are frequently described as preliminary, because most published work uses rodent or in vitro systems rather than controlled human trials. Whether the short fragment reproduces the effects of the full protein remains an open question, and the relationship between dose, route, and measured outcome is not well characterized.
The compound circulates in the literature as a research reagent rather than an approved therapeutic. Regulatory agencies in several countries have not authorized it for medical use, and sporting bodies list related thymosin beta-4 peptides among prohibited substances. Suppliers typically market it with a purity figure and a certificate of analysis, while peer-reviewed clinical reports remain sparse. Discussions therefore often separate laboratory findings from anecdotal reports, and reviewers tend to note the small size and methodological limits of the available studies.
Material sold under this label typically arrives as a freeze-dried powder in a sealed vial with a certificate of analysis. Such certificates usually report reversed-phase chromatography purity plus a mass confirmation, and stated purities commonly sit between 95 and 99 percent. Counter-ion identity, residual trifluoroacetate, water content, and peptide net weight are separate specifications that a certificate may or may not include. A purity figure alone does not establish sequence identity, so independent mass verification remains the practical check.
The designation TB-500 circulates in laboratory and catalog contexts without a single agreed definition. Most product listings apply it to an N-terminally acetylated seven-residue fragment of thymosin beta-4, while other listings attach the same label to the full 43-residue protein. Because the term is commercial rather than systematic, two entries bearing identical names may describe different molecules. Any documentation should therefore state which sequence a given sample is claimed to contain.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid as supplied |
| Water solubility | Soluble | Dissolves in aqueous media |
| Typical storage temperature | -20 °C | Dry powder, desiccated, protected from light |
| Typical analytical method | RP-HPLC with mass spectrometry | Purity from peak area; mass for identity |
| Common synonyms | Tβ4 fragment; thymosin beta-4 fragment | Naming varies by supplier and catalogue |
Discussion of TB-500 appears in several distinct literatures that rarely cite one another. Peer-reviewed studies usually describe in vitro assays or small animal experiments and are cautious about extrapolation. Veterinary and sports communities circulate anecdotal reports with limited methodological detail. Commercial listings add a third layer, often using the name interchangeably with thymosin beta-4 even though the two molecules differ in size and sequence. Regulatory status varies by country, and the compound is not a licensed medicine in most jurisdictions, so readers comparing sources should check which molecule and which purity each source actually describes.
TB-500 is a synthetic seven-residue peptide whose sequence, LKKTETQ, matches the N-terminal actin-binding region of thymosin beta-4. It is usually supplied in an N-terminally acetylated form, a modification that blocks the free amino terminus and can influence behavior in solution. In the research literature the same sequence appears under several names, including thymosin beta-4 fragment and shortened thymosin beta-4. Because it is a short peptide rather than the full 43-residue parent protein, its measured properties differ from those reported for thymosin beta-4 as a whole, and the two are not interchangeable in experimental design.
Thymosin beta-4 contains 43 amino acids and has a reported molecular mass near 4963 Da. The short fragment most often associated with the TB-500 label, an acetylated chain beginning LKKTETQ, has a reported mass near 889 Da, so the two are easily separated in analytical work. Mass spectrometry and amino acid analysis can confirm which material is present in a given sample. Statements treating TB-500 and thymosin beta-4 as interchangeable are therefore imprecise, even though the two appear together in much of the same literature.
Interest in the compound comes largely from studies of the parent protein, which participates in actin sequestration, cell migration and tissue repair processes. Whether a short fragment reproduces those activities is a separate question that remains open in the published record. Many summaries describe mechanisms by analogy to thymosin beta-4 rather than from direct measurements on the fragment. Claims about activity should be treated as provisional unless a cited study specifies the exact peptide, its purity and the assay used.
TB-500 is a laboratory label applied to a short synthetic peptide that is widely described as a fragment of thymosin beta-4, an actin-binding protein present in most mammalian cells. Suppliers and review articles usually present TB-500 as the N-terminal region of that protein, but the exact sequence attached to the name is not consistent across sources. Some product descriptions list a seven-residue chain; others use the label loosely for the parent protein itself. Because of that variation, any technical discussion of TB-500 needs to state which sequence is meant.
TB-500 is a synthetic peptide whose sequence corresponds to a short fragment near the N-terminus of thymosin beta-4, a small protein present in most mammalian cells. The fragment is commonly cited as containing the actin-binding region of the parent molecule, which is why it appears in laboratory work on cell migration and tissue repair. Suppliers distribute it as a lyophilised powder intended for research use. Its identity is defined by amino acid sequence and by the presence of an acetyl group on the N-terminal residue.
Full-length thymosin beta-4 consists of roughly forty-three amino acids and ranks among the more abundant small proteins in the cytoplasm. The fragment is much shorter, so it cannot reproduce every function attributed to the intact molecule. In cell culture, short actin-binding motifs can interfere with filament dynamics and cell movement, but such observations come from controlled experiments rather than from whole-animal work. Whether a truncated fragment produces the same effects as the parent protein remains an open question.
==== 3.A. P-P-bond hydrolysis-driven transporters ==== 3.A.1 ABC transporters including BtuCD, molybdate uptake transporter, Cystic fibrosis transmembrane conductance regulator and others 3.A.2 The H+- or Na+-translocating F-type ATPase, V-type ATPase and A-type ATPase superfamily 3.A.3 The P-type ATPase Superfamily 3.A.4 The Arsenite-Antimonite efflux family 3.A.5 General secretory pathway (Sec) translocon (preprotein translocase SecY) 3.A.6 The Type III (Virulence-related) Secretory Pathway (IIISP) Family 3.A.7 The Type IV (Conjugal DNA-Protein Transfer or VirB) Secretory Pathway (IVSP) Family 3.A.8 The Mitochondrial Protein Translocase (MPT) Family 3.A.9 The Chloroplast Envelope Protein Translocase (CEPT or Tic-Toc) Family 3.A.10 H+, Na+-translocating Pyrophosphatase family 3.A.11 The Bacterial Competence-related DNA Transformation Transporter (DNA-T) Family 3.A.12 The Septal DNA Translocator (S-DNA-T) Family 3.A.13 The Filamentous Phage Exporter (FPhE) Family 3.A.14 The Fimbrilin/Protein Exporter (FPE) Family 3.A.15 The Outer Membrane Protein Secreting Main Terminal Branch (MTB) Family 3.A.16 The Endoplasmic Reticular Retrotranslocon (ER-RT) Family 3.A.17 The Phage T7 Injectisome (T7 Injectisome) Family 3.A.18 The Nuclear mRNA Exporter (mRNA-E) Family 3.A.19 The TMS Recognition/Insertion Complex (TRC) Family 3.A.20 The Peroxisomal Protein Importer (PPI) Family 3.A.21 The C-terminal Tail-Anchored Membrane Protein Biogenesis/ Insertion Complex (TAMP-B) Family 3.A.22 The Transcription-coupled TREX/TAP Nuclear mRNA Export Complex (TREX) Family 3.A.23 The Type VI Symbiosis/Virulence Secretory Pathway (VISP) Family 3.A.24 Type VII or ESX Protein Secretion System (T7SS) Family 3.A.25 The Symbiont-specific ERAD-like Machinery (SELMA) Family 3.A.26 The Plasmodium Translocon of Exported proteins (PTEX) Family
Fluent in Hungarian and deeply sympathetic to the Hungarian cause, Elisabeth fostered close relationships with Hungarian leaders, including Count Gyula Andrássy, and worked behind the scenes to persuade Francis Joseph to adopt a more conciliatory approach. Her influence helped build the trust necessary for successful negotiations, and her personal popularity in Hungary significantly bolstered the monarchy's legitimacy in the region. Political difficulties in Austria mounted continuously through the late 19th century and into the 20th century. However, Franz Joseph remained immensely respected; the emperor's patriarchal authority held the Empire together while the politicians squabbled among themselves.
==== MeSH D12.776.964.700.750 – retroviridae proteins, oncogenic ==== MeSH D12.776.964.700.750.320 – fusion proteins, gag-onc MeSH D12.776.964.700.750.320.700 – oncogene protein p65(gag-jun) MeSH D12.776.964.700.750.470 – gene products, rex MeSH D12.776.964.700.750.480 – gene products, tax (gene) MeSH D12.776.964.700.750.650 – oncogene protein gp140(v-fms) MeSH D12.776.964.700.750.710 – oncogene protein p21(ras) MeSH D12.776.964.700.750.750 – oncogene protein p55(v-myc) MeSH D12.776.964.700.750.760 – oncogene protein pp60(v-src) MeSH D12.776.964.700.750.817 – oncogene protein v-maf MeSH D12.776.964.700.750.875 – oncogene proteins v-abl MeSH D12.776.964.700.750.882 – oncogene proteins v-erba MeSH D12.776.964.700.750.883 – oncogene proteins v-erbb MeSH D12.776.964.700.750.887 – oncogene proteins v-fos MeSH D12.776.964.700.750.900 – oncogene proteins v-mos MeSH D12.776.964.700.750.903 – oncogene proteins v-myb MeSH D12.776.964.700.750.920 – oncogene proteins v-raf MeSH D12.776.964.700.750.925 – oncogene proteins v-rel MeSH D12.776.964.700.750.935 – oncogene proteins v-sis
==== Liver toxicity ==== Although rare, flutamide has been associated with severe hepatotoxicity and death. By 1996, 46 cases of severe cholestatic hepatitis had been reported, with 20 fatalities. There have been continued case reports since, including liver transplants and death. A 2021 review of the literature found 15 cases of serious hepatotoxicity in women treated with flutamide, including 7 liver transplantations and 2 deaths. Based on the number of prescriptions written and the number of cases reported in the MedWatch database, the rate of serious hepatotoxicity associated with flutamide treatment was estimated in 1996 as approximately 0.03% (3 per 10,000). However, other research has suggested that the true incidence of significant hepatotoxicity with flutamide may be much greater, as high as 0.18 to 10%. Flutamide is also associated with liver enzyme elevations in up to 42 to 62% of patients, although marked elevations in liver enzymes (above 5 times upper normal limit) occur only in 3 to 5%. The risk of hepatotoxicity with flutamide is much higher than with nilutamide or bicalutamide. Lower doses of the medication appear to have a possibly reduced but still significant risk. Liver function should be monitored regularly with liver function tests during flutamide treatment. In addition, due to the high risk of serious hepatotoxicity, flutamide should not be used in the absence of a serious indication. The mechanism of action of flutamide-induced hepatotoxicity is thought to be due to mitochondrial toxicity.
The three substrates of this enzyme are salutaridine, reduced nicotinamide adenine dinucleotide phosphate (NADPH), and a proton. Its products are salutaridinol and oxidised NADPH+. This conversion is part of the morphinan alkaloid pathway in Papaver somniferum. The enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is salutaridinol:NADP+ 7-oxidoreductase.
Sources: en.wikipedia.org
For centuries, the Danes and Saxons had regarded each other as kindred peoples, sharing the same belief in the Germanic pantheon and frequently intermarrying, especially among the elite. Thus, the defeated Saxon warleader Widukind sought refuge with his father-in-law, Danish king Sigfred. The Royal Frankish Annals mentions that Widukind received substantial aid from Sigfred, though the exact nature of this aid is not explicitly stated. However, the chronicles do note that Sigfred and Charlemagne brokered a peace agreement some years later, indicating that Sigfred, upon hearing Widukind's plea, may have mustered his army and joined the war on the side of the Saxons. In response to the Danes' involvement in the war, Charlemagne seems to have recruited the Obotrites by promising them the Saxon portion of Holstein. This alliance with Charlemagne shifted the balance of power in the region. In 782, after another defeat of the Saxons, Charlemagne ordered the mass execution of 4,500 Saxons, an atrocity that became known as the Massacre of Verden. Following this brutal act, Charlemagne was nicknamed the "Butcher of Saxons" or "Saxonslaughterer." In 796, despite Saxony being fully under Frankish rule, the Saxons rose once more, supported by the Danes. The rebellion was triggered by the forced conscription of Saxons for the Frankish wars against the Avars. Moreover, Charlemagne, in alliance with the Obotrites, planned to subjugate the Danes, now led by King Gudfred Sigfredson. However, Gudfred struck first.
In June 2015, Chipotle began test marketing a pork and chicken chorizo-type sausage as a new protein option at selected locations in the Kansas City area. Some food writers have expressed their health related concerns over the protein's relatively high sodium content since a 4-ounce (110 g) serving contains 293 calories and 803 milligrams of sodium while the American Heart Association's recommended daily amount is less than 1,500 milligrams of sodium. In contrast, the protein options with next highest sodium contents are Barbacoa with 530 milligrams and sofritas with 555 milligrams. An earlier version of the Mexican sausage was tested in Denver and New York City in 2011, but that test was terminated when that version of the sausage was perceived as looking too greasy. Chorizo was discontinued in September 2017 but was returned to the menu in the following year for a limited time. In July 2020, Chipotle began test marketing a cauliflower rice option at 55 locations in Colorado and Wisconsin. In August 2021, Chipotle began testing a company-made vegan chorizo made with pea protein. The vegan chorizo (now called plant-based chorizo) was subsequently released nation-wide as a limited-time only item on January 3, 2022, before being removed on March 4, 2022. Chipotle accepts fax orders, and in 2005 the company added the ability to order online from their website. For both online and fax orders, customers proceed to the front of the line to pay for pre-ordered food.
==== Absorption ==== 2C-B appears to have relatively low oral bioavailability. The time to peak levels is 2.0 to 2.4 hours. Peak levels of 2C-B have been reported to be 2.5 ng/mL with 10 mg orally, 3.3 to 4.6 ng/mL with 20 mg orally, and 5.4 to 6.4 ng/mL with 30 mg orally. The peak levels of 2C-B metabolites have also been described.
Acta Biochimica et Biophysica Sinica (ABBS) is a peer-reviewed scientific journal which publishes original research articles, short communications, and reviews in the fields of biochemistry and biophysics. Established in 1958, the journal is sponsored by the Institute of Biochemistry and Cell Biology, an institute of the Chinese Academy of Sciences, and is published monthly by Oxford Journals and was published by Blackwell Publishing prior to January 2009. This journal is indexed in the following databases: Science Citation Index Expanded Zoological Record BIOSIS Previews Chemical Abstracts Service – CASSI Index medicus MEDLINE PubMed
Prior to the development of intradialytic parenteral nutrition in the late 20th century, nutritional management of patients receiving dialysis primarily relied on dietary counselling, liberalized renal diets, and oral nutritional supplements; however, protein–energy wasting (PEW) remained common among patients undergoing maintenance hemodialysis. Efforts to supplement nutritional intake by providing nutrients during the dialysis procedure were attempted. As a result, IDPN became an established therapy to threat malnourished CKD stage 5 dialysis patients in the early 1990s. Generally, the patients received a set formulation containing standard amounts of dextrose, amino acids and lipids regardless of the patient's weight, dialysis time, and complicating co-morbid conditions.
Sources: en.wikipedia.org
Oligonucleotides are chemically synthesized using building blocks called nucleoside phosphoramidites. These can be normal or modified nucleosides which have protecting groups to prevent their amines, hydroxyl groups and phosphate groups from interacting incorrectly. One phosphoramidite is added at a time, the 5' hydroxyl group is deprotected and a new base is added and so on. The chain grows in the 3' to 5' direction, which is backwards relative to biosynthesis. At the end, all the protecting groups are removed. Nevertheless, being a chemical process, several incorrect interactions occur leading to some defective products. The longer the oligonucleotide sequence that is being synthesized, the more defects there are, thus this process is only practical for producing short sequences of nucleotides. The current practical limit is about 200 bp (base pairs) for an oligonucleotide with sufficient quality to be used directly for a biological application. HPLC can be used to isolate products with the proper sequence. Meanwhile, a large number of oligos can be synthesized in parallel on gene chips. For optimal performance in subsequent gene synthesis procedures they should be prepared individually and in larger scales.
Romanowsky was the first to realise the differences in the staining abilities of eosin and methylene blue. The individual stains (monochromatic staining) were good only for general colouring of tissue or cell, but not for contrasting the different components. By mixing specific amount of eosin and methylene blue, Romanowsky found that the mixture gave images of contrasting clarity that helped to visualise different parts and components of cells. This mixture method, polychromatic staining or polychromy, with various modifications became the most efficient way of staining cells for identifying cellular components. The chemical phenomenon by which a mixture of stains produces vibrant cell images is known as "Romanowsky effect". In December 1890, Romanowsky published his invention as a preliminary report of his major work for his doctoral thesis in the journal Vrach as "On the question of the structure of malaria parasites" (as translated in English). Incorrectly, it is more often recorded in books and journals that Romanowsky published his findings in 1891, which led to a controversy on priority that Ernst Malachowsky independently developed the technique as the latter published his research in August 1891.
=== Bone, tendon, and dental repair === Common bone defects result from osteoporosis, traumatic fractures, periodontal disease, birth defects, and genetic disorders. Collagen is used in bone repairs because its triple-helix structure makes it a strong, versatile compound in biomaterials made with collagen, which provides a matrix for cells to infiltrate and help to proliferate osteoblast deposits. Tendon injuries occurring from overuse or trauma can be facilitated for healing by enabling vascular regrowth and fibroblast production using collagen-based biomaterial scaffolds. For dental applications, an absorbable collagen sponge can be packed into a root canal or the space after tooth extraction to promote blood clotting, gum regeneration, and antibacterial activity.
== Features == Each issue includes a "Making-of" article on a particular game, usually including an interview with one of the original developers. Issue 143 introduced the "Time Extend" series of retrospective articles. Like the "making-of" series, each focuses on a single game and, with the benefit of hindsight, gives an in-depth examination of its most interesting or innovative attributes. "Codeshop" examines more technical subjects such as 3D modelling programs or physics middleware, while "Studio Profile" and "University Profile" are single-page summaries ("like Top Trumps, but for game dev") of particular developers or publishers, and game-related courses at higher education institutions. Although an overall list of contributors is printed in each issue's indicia, the magazine typically has not used bylines to credit individual writers to specific reviews and articles, instead only referring to the anonymous Edge as a whole. Since 2014, some contributed features are credited with a byline. The magazine's regular columnists have been consistently credited throughout the magazine's run. The current columnists are James Leach, Clint Hocking and Tadhg Kelly. In addition, several columnists appear toward the beginning of the magazine to talk about the game industry as a whole, rather than focusing on specific game design topics. They are Trigger Happy author Steven Poole, Leigh Alexander, and Brian Howe, whose parody article section "You're Playing It Wrong" began with the new redesign.
Sources: en.wikipedia.org
TB-500 is a name used for a short synthetic peptide fragment taken from the actin-binding region of thymosin beta-4. Material sold under this label is usually a lyophilized powder supplied for laboratory research rather than a licensed medicine. The commonly cited sequence is LKKTETQ.
The parent protein contains forty-three amino acids, while the fragment carries only a short motif from one region. The fragment can interact with actin in vitro, but it does not include the rest of the protein structure. Whether the shorter molecule behaves the same way in living systems is not settled.
Published controlled human studies are scarce, and most activity reports come from cell culture or animal models. Reviews often describe the evidence base as limited and methodologically uneven. Open questions include the relationship between route, dose, and measured outcomes.
Usually not, though usage overlaps. The label most often refers to a short acetylated fragment of the parent protein, while thymosin beta-4 itself is the full 43-residue molecule. Because suppliers vary, a sequence statement is needed to settle the question for any particular lot.