This is a working overview of Thymosin beta-4, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
Material is normally supplied as a lyophilised powder in a sealed vial. The powder is hygroscopic, so exposure to humid air leads to water uptake, caking and gradual loss of the fluffy texture that indicates a good freeze-dry. Vials are best kept sealed with desiccant, protected from light and stored cold. Letting a cold vial warm to room temperature before opening reduces condensation on the contents. Purity is normally reported from a chromatographic run, and that figure applies to the batch as tested rather than to the vial after repeated opening.
Once dissolved, the peptide is far less stable than the dry powder. Aqueous solutions are subject to hydrolysis, oxidation at susceptible residues and gradual loss of material through adsorption onto glass and plastic surfaces. Terminal glutamine can cyclise under some conditions, producing a related species that complicates purity assessment. Dilute solutions tend to lose a larger fraction of material to surfaces than concentrated ones. Buffers, pH and ionic strength all influence the rate of change, so stability figures are only meaningful when those parameters are stated alongside the storage interval.
| Property | Value | Notes |
|---|---|---|
| Generic designation | Synthetic thymosin beta-4 N-terminal fragment | Peptide nomenclature varies by supplier |
| Peptide length | Approximately 17 amino acid residues | Reported length sometimes differs between sources |
| N-terminal modification | Acetyl group | Affects mass and chromatographic behaviour |
| Compound class | Small synthetic peptide | Not a small-molecule drug |
| Common synonyms | TB4 fragment; thymosin beta-4 fragment | Naming is inconsistent in popular media |
The compound is most often distributed as a lyophilized powder, appearing white to off-white and forming a loose cake or fluffy solid. It is hygroscopic to some degree, so brief exposure to humid air can add water weight and complicate weighing. The peptide dissolves readily in water and in neutral aqueous buffers, and aqueous solubility is generally described as high, well above the concentrations used in typical assays. Some polar organic solvents are also usable, which matters when a concentrated stock is prepared before dilution into buffer.
Storage recommendations center on keeping the dry powder cold, dry, and dark. A freezer at -20 degrees Celsius or below is conventional, and desiccant is often included to limit moisture uptake. Once dissolved, the peptide is less stable, and solutions are typically kept frozen and thawed only once. Repeated freeze-thaw cycles are a common source of losses because they promote aggregation and adsorption to container surfaces. Working aliquots are therefore prepared in advance, and glass or low-binding plastic is usually preferred over ordinary laboratory plastic.
TB-500 is a catalogue name applied to a synthetic peptide related to thymosin beta-4, an actin-binding protein found in most mammalian cells. Suppliers do not use the label consistently: some describe it as the full 43-residue protein, others as a short fragment from the actin-binding region, and others as a related tetrapeptide. Because the name is commercial rather than chemical, two products sold under it may not contain the same molecule. This naming ambiguity is the first point to check in any description of the material.
The most frequently cited identity is a seven-residue fragment with the sequence LKKTETQ, taken from the actin-binding domain of the parent protein. A separate molecule, N-acetyl-seryl-aspartyl-lysyl-proline, often shortened to Ac-SDKP, derives from the same protein's N-terminal region and appears in overlapping literature. Reported molecular masses therefore differ between sources, and a mass value on its own does not establish which fragment is present. Confirmation requires a defined sequence rather than a single number.
High mass accuracy: The mass deviation of the input spectra should be within 20 ppm. Mass spectrometry devices such as TOF, Orbitrap and FT-ICR usually provide data with high mass accuracy, as do coupled devices such as Q-TOF, IT-TOF or IT-Orbitrap. Spectra measured with a quadrupole or linear trap do not provide the required accuracy for data analysis with SIRIUS. Rich fragmentation spectra: It is not possible to deduce the structure or even the molecular formula from an MS2 spectrum that contains almost no peaks. Prior noise filtering of the spectra is not necessary and not favorable. SIRIUS considers up to 60 peaks in the fragmentation spectrum and decides for itself which of these peaks are regarded as noise. Centroided MS data: SIRIUS does not contain routines for peak picking from profile-mode spectra. msConvert in ProteoWizard can be used to convert to centroided data. Additionally, there are several tools specialized for the preprocessing task, such as OpenMS, MZmine or XCMS. OpenMS and MZmine 3 both provide export functions tailored to the needs for SIRIUS. Different common MS file formats, such as .csv, .ms or .mgf files, can be imported to SIRIUS. SIRIUS can import full LC-MS-runs (.mzML) or single compounds. At present, SIRIUS only handles single-charged compounds.
== Medical uses == When used in low doses, corticosteroids serve as an anti-inflammatory agent. At higher doses, they are considered as immunosuppressants. Corticosteroids inhibit the inflammatory response to a variety of inciting agents and, it is presumed, delay or slow healing. They inhibit edema, fibrin deposition, capillary dilation, leukocyte migration, capillary proliferation, fibroblast proliferation, deposition of collagen, and scar formation associated with inflammation.
The race is temporarily delayed but goes ahead, with the race being won by Kitty's Light. 24 people are subsequently charged in connection with the disruption. 25 April – The Scottish Government introduces the Victims, Witnesses, and Justice Reform (Scotland) Bill, which includes measures to scrap the verdict of not proven and to reduce the number of jurors in Scottish trials from 15 to 12; bringing Scots law in line with England. The bill will also provides for a pilot scheme whereby some rape trials will be held without a jury. 28 April The Crown Office confirms it will appeal against the sentence of Sean Hogg, a man given community service for the rape of a 13-year-old girl he committed as a minor, as unduly lenient. The Stone of Destiny leaves Edinburgh Castle for the first time in 25 years to be part of the Coronation ceremony of Charles III. 29 April – The constituency Labour parties of Rutherglen and Hamilton, Larkhall and Stonehouse have written to Labour leader Sir Keir Starmer and Scottish Labour leader Anas Sarwar to make a formal complaint about the selection process for candidates, after being "inundated" with complaints by local members about a "lack of transparency".
Sources: en.wikipedia.org
There has been a growing interest in the application of ion chromatography in the analysis of pharmaceutical drugs. Ion chromatography is used in different aspects of product development and quality control testing. For example, ion chromatography is used to improve stabilities and solubility properties of pharmaceutical active drugs molecules as well as used to detect systems that have higher tolerance for organic solvents. Ion chromatography has been used for the determination of analytes as a part of a dissolution test. For instance, calcium dissolution tests have shown that other ions present in the medium can be well resolved among themselves and also from the calcium ion. Therefore, ion chromatography has been employed in drugs in the form of tablets and capsules in order to determine the amount of drug dissolve with time. Ion chromatography is also widely used for detection and quantification of excipients or inactive ingredients used in pharmaceutical formulations. Detection of sugar and sugar alcohol in such formulations through ion chromatography has been done due to these polar groups getting resolved in ion column. Ion chromatography methodology also established in analysis of impurities in drug substances and products. Impurities or any components that are not part of the drug chemical entity are evaluated and they give insights about the maximum and minimum amounts of drug that should be administered in a patient per day.
== Mechanism of action == Asparagopsis seaweed naturally contains halogenated methane analogues, mainly bromoform (CHBr3) at 1.7% dry weight, as a form of antibacterial defense. These chemicals act as an inhibitor for cobamide-dependent methyltransferase (see: Coenzyme M), a key enzyme for methanogenesis.
Insulin-dependent (type I) diabetes mellitus (IDDM) is a genetic heterogenous autoimmune disorder, which is triggered by genetic predisposition and environmental factors. The prevalence of insulin-dependent (type I) diabetes mellitus (IDDM) among children and young adult from Europe is approximately 0.4%. Insulin-dependent (type I) diabetes mellitus (IDDM) is characterized by acute onset and insulin deficiency. Patients with insulin-dependent (type I) diabetes mellitus (IDDM) are found with gradual loss of the pancreatic islet beta cells and therefore not able to produce insulin. As a result, they usually need exogenous insulin to maintain their life.
Sources: en.wikipedia.org
Under the 2017 constitution, prime ministers may only be chosen from a pre-declared list of candidates. Each party may submit up to three names and must have at least 5% (25 members) in the House of Representatives to receive eligibility. Candidates did not have to be a member of parliament (MP).
Y-90, used for treating lymphoma (2.7 days) I-131, used for thyroid function tests and for treating thyroid cancer (8.0 days) Sr-89, used for treating bone cancer, intravenous injection (52 days) Ir-192, used for brachytherapy (74 days) Co-60, used for brachytherapy and external radiotherapy (5.3 years) Cs-137, used for brachytherapy and external radiotherapy (30 years) Tc-99, product of the decay of technetium-99m (221,000 years)
Insulin detemir is a long-acting modified form of medical insulin used to treat both type 1 and type 2 diabetes. It is administered through subcutaneous injection. Its effects last for up to 24 hours. Common side effects include (hypoglycemia, allergic reactions, pain at the injection site, and weight gain. It appears to be safe for use during pregnancy and breastfeeding. Insulin detemir works by increasing the amount of glucose absorbed by tissues and reducing the amount of glucose produced by the liver. Insulin detemir was approved for medical use in the European Union in June 2004 and in the United States in June 2005. It is listed on the World Health Organization's List of Essential Medicines. In 2022, it was the 127th most commonly prescribed medication in the United States, with over 4 million prescriptions. Insulin detemir is only sold under the name Levemir by Novo Nordisk, who owned its patent until 2019. in certain countries, Levemir and certain related products were discontinued in 2024.
Sources: en.wikipedia.org
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.
No. Thymosin beta-4 is the full-length protein of about forty-three amino acids, while the fragment covers only its beginning. The two are related but are not interchangeable in experimental or analytical terms.
The label is a catalogue designation that became common in non-technical discussion. Scientific papers usually refer to the fragment by sequence or as a thymosin beta-4 N-terminal peptide.
Sealed, dry and protected from light at reduced temperature is the usual laboratory convention. Allowing a cold vial to reach room temperature before opening limits condensation. Repeated opening exposes the powder to moisture and should be minimised.