A practical reference on thymosin beta-4: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-09-02 and is reviewed periodically as new material appears.
TB-500 is a research peptide whose sequence matches residues 17 to 23 of thymosin beta-4, a 43-residue protein present in most mammalian cells. The chain is seven amino acids long, written as LKKTETQ, and is normally supplied with an acetyl group on the N-terminus. Suppliers list it as a lyophilised powder under the code name TB-500, and the same sequence appears elsewhere in catalogues as the thymosin beta-4 actin-binding fragment. The label is commercial rather than systematic, so no single authority fixes exactly what TB-500 denotes.
Thymosin beta-4 was isolated from calf thymus in the early 1980s and later characterised as an abundant intracellular actin-sequestering protein. Interest in short synthetic fragments grew once the actin-binding motif had been mapped to the middle of the sequence. TB-500 came out of that line of work as a truncated analogue rather than a natural isolate, and it is now sold mainly to laboratories. Published studies on the fragment have been largely in vitro or in animal models, and controlled human trials remain sparse, so claims about effects in people rest on extrapolation.
Reconstitution of a lyophilized peptide is normally done with sterile water or a suitable buffer under aseptic conditions. Adding solvent down the vial wall and allowing gentle dissolution instead of vigorous vortexing reduces the chance of aggregation, which can lower the effective concentration of the resulting solution. Concentrated stocks are usually diluted into working buffer shortly before use. Because no standard preparation protocol exists for TB-500 specifically, laboratories adapt general peptide handling practice, and reported results may reflect differing preparation choices.
Dry peptide powder is commonly kept at −20 °C in a desiccated container away from light, a practice that limits moisture uptake and oxidation. Once dissolved, solutions are generally held at 2–8 °C for short periods or frozen at −20 °C or lower for longer storage, with repeated freeze-thaw cycles avoided. Hydrolysis and oxidation are the main degradation routes for peptides in solution, and both accelerate at higher temperature or extreme pH. Published stability data specific to TB-500 are limited, so shelf life should be treated as uncertain.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Supplied as a lyophilised cake in sealed vials |
| Solubility class | Freely soluble in water | Polar and charged side chains dominate the sequence |
| Typical storage temperature | -20 °C or below | Dry and dark; a desiccant is often recommended |
| Identity confirmation | Mass spectrometry | Observed mass compared with the theoretical value |
| Common synonyms | Thymosin beta-4 fragment | Also written as T beta 4 fragment 17-23 |
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.
Peptide bonds are susceptible to hydrolysis under extreme pH and to enzymatic cleavage if proteases are present. Heat, oxidising agents, and prolonged exposure to light also contribute to loss of material. Aggregation can occur at high concentrations or in certain buffer systems, and it may not be visible to the eye. Storage at -20 C or below is typical for both powder and aliquoted solutions, and desiccation of the powder is preferred.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography together with mass spectrometry. The chromatogram provides a purity estimate as a percentage of total peak area, while the mass spectrum confirms that the observed mass matches the expected value. Amino acid analysis or tandem mass spectrometry sequencing can provide additional confirmation. Reported purity figures depend on the column, gradient, and detection wavelength, so values from different laboratories are not directly comparable without method details.
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== Personal life == Jennette is married to Yvonne Cahoon Jennette. They have two daughters, Jennifer Jennette, and Caroline Poulton; and three grandchildren, Olivia Meyer-Jennette, Augusta Meyer-Jennette, and Quinn Poulton.
The use of electron cyclotron resonance (ECR) ion sources for the production of intense beams of highly charged ions has immensely grown over the last decade. ECR ion sources are used as injectors into linear accelerators, Van-de-Graaff generators or cyclotrons in nuclear and elementary particle physics. In atomic and surface physics ECR ion sources deliver intense beams of highly charged ions for collision experiments or for the investigation of surfaces. For the highest charge states, however, Electron beam ion sources (EBIS) are needed. They can generate even bare ions of mid-heavy elements. The Electron beam ion trap (EBIT), based on the same principle, can produce up to bare uranium ions and can be used as an ion source as well.
Sources: en.wikipedia.org
=== Microanatomy === The choroid plexus consists of a layer of cuboidal epithelial cells surrounding a core of capillaries and loose connective tissue. The epithelium of the choroid plexus is continuous with the ependymal cell layer (ventricular layer) that lines the ventricular system. Progenitor ependymal cells are monociliated but they differentiate into multiciliated ependymal cells. Unlike the ependyma, the choroid plexus epithelial layer has tight junctions between the cells on the side facing the ventricle (apical surface). These tight junctions prevent the majority of substances from crossing the cell layer into the cerebrospinal fluid (CSF); thus the choroid plexus acts as a blood–CSF barrier. The choroid plexus folds into many villi around each capillary, creating frond-like processes that project into the ventricles. The villi, along with a brush border of microvilli, greatly increase the surface area of the choroid plexus. CSF is formed as plasma is filtered from the blood through the epithelial cells. Choroid plexus epithelial cells actively transport sodium ions into the ventricles and water follows the resulting osmotic gradient. The choroid plexus consists of many capillaries, separated from the ventricles by choroid epithelial cells. Fluid filters through these cells from blood to become cerebrospinal fluid. There is also much active transport of substances into, and out of, the CSF as it is made.
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=== Austria === A member of Parliament is a member of either of the two chambers of the Parliament of Austria (Österreichisches Parlament). The members of the Nationalrat are called Abgeordnete zum Nationalrat. The members of the Bundesrat, elected by the provincial diets (Landtage) of the nine federal States of Austria, are known as Mitglieder des Bundesrats.
Sources: en.wikipedia.org
Mriganka Sur (born 1953 in Fatehgarh, India) is an Indian-American neuroscientist known for his contributions to understanding the development, organization, plasticity and computational function of the cerebral cortex. He is the Newton Professor of Neuroscience and director of the Simons Center for the Social Brain at the Massachusetts Institute of Technology. He also served as a visiting faculty member in the Department of Computer Science and Engineering at the Indian Institute of Technology Madras and N.R. Narayana Murthy Distinguished Chair in Computational Brain Research at the Centre for Computational Brain Research, IIT Madras. He was on the Life Sciences jury for the Infosys Prize in 2010, and has served as jury chair since 2018.
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== Acquisitions == In July 2016, Relief acquired FirstString Research, a clinical-stage biotech firm based in Charleston, South Carolina, US. In January 2021, Relief acquired German-based firm AdVita in a €25 million agreement to further their research into inhaled treatments for Acute respiratory distress syndrome. In May 2021, Relief acquired Swiss biotech firm Applied Pharma Research (APR), including its existing portfolio and all pipeline products, for CHF 72 million ($79 million).
Currently the railway has been under-grounded: the avenue will be enlarged and have same architecture style of southern Corso Inghilterra in downtown, becoming one of the major avenues of Turin. The northern part of the district was part of the former industrial district of Turin, recently reconverted to a park called Parco Dora. Mainly, in San Donato the portion reconverted was the one occupied by the plant of Michelin (west of Via Livorno) and Fiat ironwork plants (on the East). Differently for other portions of Parco Dora, this part has been totally reconverted to park without letting any evidence of the industrial area except for the cooling tower which stands along Corso Umbria and became a symbol of the park. Works are completed in the western area, where Corso Mortara has been closed to traffic and moved just a bit northern and covered by an artificial tunnel. It is possible to access the southern shore of the River Dora. South of the park, an interesting architecture of different levels is hosting a new shopping mall called Centro Commerciale Parco Dora. East of Via Livorno, works are still partially in progress, with the River Dora still to be uncovered by a big slab, on which the Fiat plants used to stand). West of Via Livorno, the Environment Park is a research centre for renewable energy.
Sources: en.wikipedia.org
No. Thymosin beta-4 is a 43-residue protein, while TB-500 matches only residues 17 to 23 of that chain. The two are related but differ in size, and a method that identifies one does not automatically identify the other.
It corresponds to the actin-binding region of thymosin beta-4. Commercial synthesis reproduces that seven-residue stretch, usually with an acetyl group on the N-terminus.
It is not authorised as a medicine in the United States or the European Union and is distributed as a research chemical. Labels consequently carry research-use-only statements rather than clinical indications.
Standard practice is a desiccated container at −20 °C, protected from light and kept sealed between uses. Letting the vial reach room temperature before opening reduces condensation on the powder. Repeated warming and cooling of the whole container is generally avoided.