The short version of thymosin beta-4 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-13. Anything still debated is marked as such rather than presented as settled.
Thymosin beta-4 is a naturally occurring protein of 43 amino acids found in most mammalian cells, where it binds actin monomers and influences filament dynamics. It was first isolated from thymus tissue in the early 1980s, and its actin-binding activity was later mapped to a short region near the N-terminus. The synthetic fragment sold as TB-500 was designed to reproduce that region rather than the full protein. Whether a short fragment reproduces the behavior of the intact molecule remains an open question, since the parent protein carries additional structural elements outside the binding region.
Published research on the intact protein is substantial, covering actin regulation, cell migration, and wound models. Research using the heptapeptide fragment specifically is far smaller, and much of the circulating material originates in supplier documentation rather than peer-reviewed reports. Where fragment studies do exist, they often employ different sequences, chain lengths, or terminal modifications, which complicates direct comparison across papers. Readers encountering claims about TB-500 should therefore separate evidence about thymosin beta-4 from evidence about the fragment itself.
Discussion of the compound frequently appears alongside other short peptides described as fragments of larger proteins. That grouping is convenient but can be misleading, because fragment length, charge, and modification state determine how a peptide behaves in solution and in any experimental system. A seven-residue acetylated peptide and a full-length protein differ in mass by roughly an order of magnitude, and they cannot be assumed to share distribution or binding properties. Precision about which molecule is under discussion is the single most useful step when reading such material.
Interest in the peptide grew during the 2000s and 2010s, when studies of tendon and ligament injuries in horses reported changes in lesion size after treatment. Those reports circulated widely outside the scientific literature and shaped much of the current online discussion. Subsequent reviews noted inconsistent study design, small groups, and a shortage of independent replication. Popular descriptions often blur the line between the fragment, the complete protein, and unrelated growth factors, which complicates comparisons across sources.
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.
| Property | Value | Notes |
|---|---|---|
| Reported sequence | Ac-LKKTETQ | Described in most listings as the actin-binding region of thymosin beta-4 |
| Reported molecular weight | Approximately 889 Da | Value shifts with the stated sequence; compare against the certificate of analysis |
| Parent protein length | 43 amino acids | Thymosin beta-4; the fragment covers only a small part of it |
| Common synonyms | TB4 fragment; thymosin beta-4 fragment | Trade-style names rather than formal nomenclature |
| Formal monographs | Not established | Labeling conventions differ by supplier and region |
Thymosin beta-4 itself is a small, widely expressed protein that sequesters monomeric actin and participates in cell migration, angiogenesis, and tissue repair. Researchers have examined the shortened fragment as a possible mimic of some of these activities, reasoning that the actin-binding motif lies within the first few residues. Binding to monomeric actin has been observed in cell-free systems. Whether the fragment reproduces the broader effects of the full protein in living tissue remains an open question, and findings from animal models are frequently cited without a clear bridge to human physiology.
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.
TB-500 refers to a synthetic peptide fragment derived from the actin-binding region of thymosin beta-4, a protein present in most mammalian cells. The full protein contains forty-three amino acids, while the commonly sold fragment is a much shorter acetylated sequence, often cited as LKKTETQ. The fragment retains part of the actin-binding motif but lacks the remainder of the parent protein. Material sold under this name is usually lyophilized powder intended for laboratory research, and it is not a finished pharmaceutical product.
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.
Die Membran besteht meistens aus Siliciumdioxid oder Siliciumnitrid und hat eine geringe Wärmekapazität und einen hohen Wärmewiderstand. Dadurch erwärmt die durch den Heizer eingebrachte Heizleistung quasi nur die Membran, während der Chiprahmen nahezu auf Umgebungstemperatur bleibt. Der Aufbau in Siliciumtechnologie verringert somit die benötigte Heizleistung und ermöglicht die Massenfertigung im Batch-Prozess.
Der Taguchi-Sensor Ein bekannter Sensor ist der von Naoyoshi Taguchi entwickelte „Figaro-Sensor“ auf Zinnoxidbasis. Der Typ TGS 813 wird besonders als Nachweis für Erdgas, Methangas verwendet, der Typ TGS 822 dient zum Nachweis von Alkohol, Ammoniak usw. Schon im Jahr 1988 wurden beispielsweise 400.000 Stück des Sensors TGS 813 (guter Nachweis für Erdgas und Methan) verkauft. Die Empfindlichkeit beim Taguchi-Sensor hängt entscheidend von der durchschnittlichen Korngröße des Zinnoxids ab und diese sollte eine Korngröße von 10 nm nicht überschreiten. Bei ganz trockener Luft ist die Empfindlichkeit des TGS 822 auf Ethanol sehr stark eingeschränkt. Die Spannungsänderung sinkt stark ab. Im Bereich 30–60 % Luftfeuchtigkeit reagiert der TGS 822 auf Ethanol zwar auch auf Änderungen der Luftfeuchtigkeit, jedoch nur sehr marginal. Ist nur ein Gas vorhanden, so kann die Bestimmungen der relativen Konzentration durch Kalibrierung ermittelt werden.
===== Nachteile ===== Nichtlineare Sensorreaktion in Abhängigkeit von der Gaskonzentration hohe Drift und Alterung (Abhängig auch von Bauart: klassisch, mikromechanisch) Kalibrierung wegen Nichtlinearität schwierig Querempfindlichkeiten z. B. Luftfeuchtigkeit geringe Selektivität hoher Energieverbrauch durch erforderliche Betriebstemperatur (1–4 W) (herabgesetzt durch Miniaturisierung und Dünnschicht-Technologie)
Nichtdispersive Infrarotsensoren (NDIR) nutzen zur Messung der Gaskonzentration die unterschiedliche Absorption infraroter Strahlung durch Gase in ähnlicher Weise wie die Absorptionsspektrometrie. Im Gegensatz zur Spektrometrie wird der interessierende Spektralbereich nicht punktweise (dispersiv) durchfahren. Vielmehr wird in einem einzigen Schritt ein Summensignal gebildet.
Sources: de.wikipedia.org
Most listings describe it as a short acetylated peptide with the sequence Ac-LKKTETQ, presented as a region of thymosin beta-4. The label is a trade-style name rather than a standardized chemical name, so the exact content of a given vial depends on the supplier.
No. Thymosin beta-4 is a protein of 43 amino acids, while TB-500 is described as a short fragment of it. The two differ in size, structure, and the range of interactions each can support.
Naming for research peptides is not centrally coordinated, so vendors set their own labels and specifications. Differences in stated sequence, molecular weight, or purity documentation usually trace back to those independent labeling choices.
It is a synthetic peptide based on a short sequence near the start of thymosin beta-4. It is supplied as a research chemical rather than as a licensed pharmaceutical product.