TB-500 (Thymosin Beta-4): What Researchers Need to Know in 2026

Peptide research continues to evolve, and a handful of foundational molecules remain constant reference points. TB-500, the commercial designation used for synthetic thymosin beta-4 (Tβ4) material, is one of them. Thymosin beta-4 is one of the most abundant small peptides in mammalian cells and one of the most thoroughly characterized actin-binding molecules in cell biology. In 2026 it remains a frequently catalogued research compound, and laboratories evaluating it need a clear picture of its chemistry, its documentation and its handling.

For in-vitro laboratory research use only. Not for human consumption.

Understanding TB-500: A Deeper Dive

TB-500 refers to synthetic material corresponding to thymosin beta-4, a 43-amino acid peptide found in virtually all mammalian cell types. In cells, Tβ4 is present at high concentrations in the cytoplasm, where its most thoroughly documented role is binding monomeric actin. Synthetic thymosin beta-4 can be prepared by solid-phase peptide synthesis; Excalibur supplies TB-500 as a lyophilized powder for in-vitro laboratory research. It is not approved by the FDA for human or veterinary use.

Biochemical Function: Actin Binding

The most thoroughly characterized biochemical property of thymosin beta-4 is its interaction with actin. Actin is the most abundant protein in eukaryotic cells and forms the microfilaments of the cytoskeleton. In purified in-vitro systems, Tβ4 binds monomeric actin (G-actin) in a 1:1 complex, and this sequestration reduces the pool of monomer available for polymerization into filamentous actin (F-actin).

Sequence Features — Thymosin beta-4 has the sequence Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES. It is rich in charged residues, with nine lysines and eleven acidic residues, which makes it highly water-soluble and gives it an acidic isoelectric point near pH 5.

N-terminal Acetylation — The native peptide carries an acetyl group on its N-terminal serine. Synthetic research material reproduces this modification, and it is included in the theoretical molecular formula (C212H350N56O78S) and average molecular weight (approximately 4963.4 g/mol).

Intrinsically Disordered Structure — In aqueous solution, free Tβ4 has little stable secondary structure and behaves as an intrinsically disordered peptide. Structural studies indicate that it adopts partially helical conformations when bound to actin.

Nomenclature — "TB-500" is a commercial name rather than a term from the peer-reviewed literature, where the molecule is referred to as thymosin beta-4 or Tβ4. Suppliers use the name for material described as the full 43-residue sequence or, in some cases, a shorter fragment, so the sequence stated in the documentation should always be checked.

Related Fragments — Two shorter sequences within Tβ4 appear in the literature in their own right: the N-terminal tetrapeptide Ac-SDKP (residues 1 to 4) and the central motif LKKTETQ (residues 17 to 23), which lies within the actin-binding region. These are distinct compounds with their own molecular weights and should not be confused with the full-length peptide.

Scope of the Published Literature

Thymosin beta-4 has been examined in published in-vitro and animal research since the early 1980s. The literature spans three broad areas:

Protein Chemistry and Discovery — Tβ4 was first isolated from calf thymus preparations, and its complete amino acid sequence was reported in 1981 (Low et al., 1981). The name "thymosin" reflects that thymic origin, although later work showed the peptide is present in most cell types.

Cell Biology of Actin — In 1991, Tβ4 was identified as the principal G-actin-sequestering peptide in many cells (Safer et al., 1991), and a large body of biochemical work has since characterized its interaction with actin (Huff et al., 2001; Hannappel, 2007).

Animal Studies — Tβ4 has also been examined in a range of rodent studies, and several research groups have published on it over the past two decades (Smart et al., 2011). As with any preclinical literature, these papers document model systems and methods; they do not establish any human use, and no such use is implied here.

The Beta-Thymosin Family — Tβ4 belongs to a family of closely related small acidic peptides that also includes thymosin beta-10 and thymosin beta-15. The family members share a conserved actin-binding region, and comparative work across the family is part of the protein-chemistry literature.

TB-500 and BPC-157: Two Different Molecules

TB-500 and BPC-157 are sometimes discussed side by side because both appear in catalogues of research peptides, but they are unrelated molecules with different sequences, sizes and analytical profiles, and each has its own separate literature.

BPC-157 is a 15-residue synthetic peptide (GEPPPGKPADDAGLV, approximately 1419.5 g/mol) with unmodified termini, while TB-500 corresponds to a 43-residue acetylated peptide roughly three and a half times its mass.

The practical differences for a laboratory are chemical:

• TB-500 is a larger, highly charged, N-terminally acetylated peptide with one methionine and several asparagine and glutamine residues
• BPC-157 is a short, proline-rich sequence with no methionine, asparagine or glutamine
• The two peptides elute at different positions in reversed-phase HPLC and have very different mass spectrometric signatures
• Each requires its own analytical documentation, and each should be recorded separately in laboratory inventories

Excalibur Peptides also offers a combined research formulation of the two peptides, the Wolverine Blend. A combination product is a distinct material and should be documented as such; its analytical characterization must resolve and identify both components.

Sourcing Standards for Research Peptides

The integrity of any laboratory work depends on documented identity and composition of the materials used:

• A published Certificate of Analysis reporting HPLC purity and mass spectrometry identity
• The full sequence stated in the documentation, so it is clear whether the material is full-length Tβ4 or a fragment
• Mass spectrometry data consistent with the theoretical molecular weight, including the N-terminal acetyl group
• Salt-form information so molar calculations can be made correctly
• Stated storage conditions for the lyophilized powder, typically -20°C

TB-500 from Excalibur Peptides

Excalibur Peptides is a U.S.-based research peptide supplier. Our TB-500 is supplied as a lyophilized powder in sealed vials for in-vitro laboratory research. A Certificate of Analysis is published for this product and can be reviewed on the product page and in our COA database. See our guide to evaluating research peptide suppliers for vendor-vetting criteria.

Shop TB-500 →

References: Smart N. et al. (2011). Circ Res. 109(6):661-671 · Chopp M. et al. (2009). J Neuropathol Exp Neurol. 68(4):438-446 · Malinda K.M. et al. (1999). J Cell Physiol. 181(1):179-183 · Sikiric P. et al. (2013). J Physiol Pharmacol. 64(2):177-187

Delving Deeper: The Molecular Mechanisms of TB-500/Tβ4

While the biochemistry of thymosin beta-4 is often summarized by its role in actin sequestration, a granular examination reveals a more intricate network of molecular interactions. Understanding these pathways is critical for researchers designing in-vitro experiments and interpreting cellular responses.

The Actin Cytoskeleton: More Than Just Sequestration

The relationship between Thymosin Beta-4 (Tβ4) and actin is the cornerstone of its biological function. The cytoskeleton is not a static scaffold but a dynamic structure, constantly polymerizing and depolymerizing to facilitate cell movement, shape changes, and internal transport. Tβ4 is one of the principal monomer-binding proteins in this system.

It primarily binds to G-actin (globular or monomeric actin) via its highly conserved WH2 domain (Wiskott-Aldrich syndrome protein Homology 2). This binding accomplishes two key things:

1. Buffering G-Actin: Tβ4 sequesters G-actin monomers, creating a large intracellular pool of actin that is ready for polymerization but kept in an inactive state. This prevents spontaneous and uncontrolled filament formation, which would be energetically costly and functionally chaotic for the cell. When the cell receives a signal to move or change shape, other proteins like profilin can compete with Tβ4, releasing the G-actin monomers at the advancing edge of the cell for rapid assembly into F-actin (filamentous actin).
2. Inhibiting Nucleotide Exchange: Tβ4's binding to ATP-G-actin also slows the hydrolysis of ATP to ADP and inhibits the exchange of ADP for ATP. This is a crucial control step, as only ATP-G-actin can be efficiently added to a growing actin filament. By managing this pool, Tβ4 ensures that the building blocks for actin polymerization are readily available and in the correct form when needed.

Because actin binding is the defining biochemical property of Tβ4, the literature describes several in-vitro methods for characterizing it. These include DNase I inhibition assays (monomeric actin inhibits DNase I, and sequestration can be followed through this interaction), pyrene-labeled actin polymerization assays that report filament assembly by fluorescence, native gel electrophoresis to visualize the actin-Tβ4 complex, and chemical cross-linking. These methods are part of the protein-chemistry toolkit for studying actin-binding peptides in purified systems.

Structural Studies of the Actin-Thymosin Beta-4 Complex

Free Tβ4 in solution is largely unstructured, which made it difficult to study by crystallography on its own. Structural information has instead come from nuclear magnetic resonance (NMR) spectroscopy of the free and actin-bound peptide and from crystal structures of actin in complex with Tβ4-derived constructs (Irobi et al., 2004).

These studies describe an extended binding mode in which the N-terminal portion of Tβ4 forms a short helix that contacts one end of the actin monomer, while the C-terminal portion contacts the opposite end. The central LKKTETQ region lies along the actin surface between them. This arrangement explains how a small, flexible peptide can cover a large surface of the actin monomer and block its incorporation into filaments.

The actin-binding region of Tβ4 is related to the WH2 (WASP-homology 2) motif found in a number of other actin-binding proteins. Comparing Tβ4 with other WH2-containing proteins is a recurring theme in the structural literature.

Extracellular Tβ4 and Other Interaction Partners

Although Tβ4 lacks a classical secretion signal, it has been detected outside cells, and the literature includes proposals of extracellular interaction partners and cell-surface binding sites. This area of research is less settled than the intracellular actin-binding role and is described here only as part of the literature context.

Post-Translational Modifications of Native Tβ4

Native Tβ4 isolated from cells can carry modifications beyond N-terminal acetylation, including oxidation of methionine 6 and, in some reports, phosphorylation. Synthetic research material is generally supplied as the acetylated, unoxidized peptide. For analytical purposes, the methionine sulfoxide form is the modification most likely to be encountered, because it can form during synthesis, handling or storage. It adds 16 Da to the molecular mass and is visible as a separate species in mass spectrometry and, often, as a closely eluting peak in HPLC.

Synthesis Considerations for a 43-Residue Peptide

At 43 residues, thymosin beta-4 sits toward the upper end of what is routinely produced by stepwise solid-phase synthesis. Each coupling step is slightly less than complete, so the crude product contains a family of closely related deletion and truncation sequences in addition to the full-length peptide. The high density of lysine and glutamate residues also requires careful choice of side-chain protecting groups, and the N-terminal acetylation is performed as a final capping step before cleavage from the resin. Preparative reversed-phase HPLC separates the full-length acetylated product from these by-products, and analytical HPLC combined with mass spectrometry confirms that the final material is the intended sequence. For laboratories, the practical point is that analytical documentation is especially informative for longer peptides, because the range of possible synthesis by-products is larger.

Reading the Thymosin Beta-4 Literature

With four decades of publications, the Tβ4 literature is large and varied. For laboratories, it is most useful as a record of methods, model systems and analytical approaches. The following points help place individual papers in context.

Distinguishing Protein Chemistry From Biological Studies

A substantial part of the literature is protein chemistry: sequence determination, actin-binding measurements, structural studies and comparisons across the beta-thymosin family. These papers use purified proteins and well-defined biochemical assays. A separate part of the literature consists of cell-based and animal studies. The two bodies of work answer different kinds of questions and should be read with different expectations about reproducibility and interpretation.

Material Identity in Published Work

Published studies have used Tβ4 from several sources: peptide purified from animal sources, recombinant protein expressed in bacteria and chemically synthesized peptide. Recombinant material may lack the N-terminal acetyl group unless it is added enzymatically, and fragments are sometimes used in place of the full-length molecule. When comparing papers, it is worth checking which form was used, how it was characterized and how it was stored.

Evaluating Individual Studies

The same questions apply to Tβ4 papers as to any preclinical literature:

• Was the identity of the material confirmed by mass spectrometry?
• Were appropriate vehicle and negative controls included?
• Was the sample size stated and justified?
• Were the analyses pre-specified?
• Has the observation been reproduced by an independent laboratory?

Regulatory Status

Tβ4 has been the subject of regulated development programs, but no product containing it has been approved for human use by the FDA. Research material sold as TB-500 is not an FDA-approved drug product. It is supplied for in-vitro laboratory research only.

Analytical Documentation & Certificate of Analysis (COA) Deep Dive

For any laboratory investigation, the identity and composition of the starting material must be documented. A product-page summary is not a substitute for analytical data. The Certificate of Analysis is the document that records how a peptide was tested and what those tests showed, and understanding how to read it is a core skill for any researcher who handles peptides.

Anatomy of a Peptide COA

A COA is a technical report, not a marketing document. It records the analytical testing performed on the material it describes. The parameters below are the ones most commonly reported for TB-500.

• Product Name and Reference Number: Identifies the compound (e.g., TB-500) and links the document to the material that was analyzed.
• Molecular Formula and Molecular Weight: Theoretical values calculated from the sequence. For full-length, N-terminally acetylated Tβ4, the formula is C212H350N56O78S and the theoretical average molecular weight is approximately 4963.4 Da. These values are the reference for identity testing.
• Appearance: Lyophilized peptides should appear as a white, uniform powder or cake. Discoloration or a collapsed, sticky cake can indicate moisture uptake or degradation.
• Purity (by HPLC): The proportion of total UV-absorbing peak area attributable to the main peak, which indicates how much of the detected material is the target sequence rather than synthesis-related by-products such as truncated or deletion sequences. The detection wavelength and method conditions should be stated.
• Identity (by MS): The observed molecular mass, which should agree with the theoretical value within the instrument's stated tolerance. For a peptide of this size, the value is usually derived by deconvoluting a series of multiply charged ions.
• Net Peptide Content: Often determined by amino acid analysis or nitrogen content, this is the fraction of the powder's total mass that is peptide, with the remainder being counter-ions (such as acetate) and bound water. It is required for accurate molar quantification in analytical work.
• Water Content (by Karl Fischer): Lyophilized peptides are hygroscopic and always contain some residual water. Karl Fischer titration quantifies it precisely.
• Bacterial Endotoxins (LAL): Relevant for cell-based work, because endotoxins from Gram-negative bacteria can activate innate immune signaling in cultured cells and confound experimental readouts. When this test is performed, the COA reports the value in Endotoxin Units per milligram (EU/mg).

A transparent and detailed COA empowers the researcher to trust their materials, ensure the reproducibility of their experiments, and accurately interpret their data.

A Researcher's Guide to Analytical Testing Methodologies

To interpret the data on a COA, it helps to understand the principles behind the analytical techniques used to generate it. These methods are the basis of peptide characterization.

High-Performance Liquid Chromatography (HPLC)

Purpose: To determine the purity of the peptide sample.

Principle: HPLC is a separation technique. A small, precisely measured amount of the dissolved peptide is introduced into the system by an autosampler and pumped at high pressure through a column packed with a solid material (the stationary phase). A liquid solvent mixture (the mobile phase) carries the sample through the column.

For peptides, Reverse-Phase HPLC (RP-HPLC) is standard. The stationary phase is non-polar (hydrophobic), and the mobile phase is polar (typically a mixture of water and a more organic solvent like acetonitrile). Peptides in the sample will interact with the stationary phase to varying degrees based on their own polarity and hydrophobicity. Less polar molecules stick to the column more tightly and take longer to elute (wash out), while more polar molecules elute faster.

Output: A detector at the end of the column (usually a UV detector set to ~214 nm, the absorbance wavelength of the peptide bond) measures the amount of substance eluting over time. This generates a chromatogram—a graph of absorbance versus time. The main, target peptide should produce a large, sharp peak at a specific retention time. Impurities, being structurally different, will have different retention times and appear as smaller, separate peaks. Purity is calculated by dividing the area under the main peak by the total area of all peaks in the chromatogram.

Mass Spectrometry (MS)

Purpose: To confirm the identity and molecular weight of the peptide.

Principle: MS measures the mass-to-charge ratio (m/z) of ions. First, the peptide molecules are ionized—given an electrical charge—typically using methods like Electrospray Ionization (ESI) or Matrix-Assisted Laser Desorption/Ionization (MALDI). These charged ions are then accelerated into a magnetic or electric field within the mass analyzer.

The field deflects the ions according to their m/z ratio. Lighter ions or more highly charged ions are deflected more easily. A detector at the end of the analyzer records the m/z ratio of the ions that strike it.

Output: The instrument produces a mass spectrum—a plot of ion intensity versus m/z. For a peptide like TB-500, this spectrum will show a series of peaks corresponding to the molecule with different charge states (e.g., [M+2H]²⁺, [M+3H]³⁺, etc.). The software can de-convolute this data to calculate the original molecular mass (M) of the peptide. This "observed mass" is then compared to the "theoretical mass" calculated from the amino acid sequence. A match within a very small tolerance (e.g., ± 0.5 Da) confirms the identity of the peptide.

For full-length TB-500, the most prominent ions under electrospray conditions typically fall in the 4+ to 7+ charge states, for example near m/z 1241.9 ([M+4H]4+), 993.7 ([M+5H]5+) and 828.2 ([M+6H]6+). A companion series 16 Da heavier in the deconvoluted spectrum indicates the methionine sulfoxide variant.

Limulus Amebocyte Lysate (LAL) Test

Purpose: To detect and quantify bacterial endotoxins.

Principle: This fascinating assay utilizes a biological cascade. The key reagent is a lysate (cellular extract) from the amebocyte blood cells of the Atlantic horseshoe crab (Limulus polyphemus). The lysate contains enzymes that are extremely sensitive to the presence of bacterial endotoxins.

In the presence of endotoxin, an enzyme cascade is initiated within the lysate, culminating in the cleavage of a pro-clotting enzyme. In older gel-clot methods, this would cause the lysate to form a solid gel. In modern quantitative methods (chromogenic or turbidimetric), the activated enzyme cleaves a synthetic substrate, producing a color change or increase in turbidity. The rate or amount of this change is directly proportional to the amount of endotoxin present in the sample and can be measured with a spectrophotometer.

Comparative Chemistry of TB-500 and BPC-157

TB-500 and BPC-157 are frequently listed together in research catalogs, and they are sometimes combined in a single research formulation. As chemicals, however, they are very different. The following table compares the two molecules on the properties that matter most for analysis, documentation and storage.

Logistics, Handling, and Preparation for Laboratory Use

The integrity of a research peptide depends not only on how it was made but also on how it is shipped, stored and handled in the laboratory. Sound storage and handling practices prevent degradation and support reproducible work.

From Synthesis to Lab: The Importance of Storage

Research peptides are the product of a manufacturing and logistics process designed to maximize stability.

1. Synthesis and Purification: Peptides like TB-500 are built amino acid by amino acid using solid-phase peptide synthesis (SPPS). For a 43-residue sequence, coupling efficiency at every step matters, because small losses per step accumulate into a significant fraction of truncated sequences. After cleavage from the resin, the crude peptide is purified by preparative HPLC.
2. Lyophilization: The purified peptide, dissolved in a water/acetonitrile solution, is frozen and placed under a high vacuum. This process, called lyophilization (or freeze-drying), removes the solvent by sublimation and leaves a stable, dry powder suited to long-term storage and shipping.
3. Storage and Shipping: Lyophilized peptides are stable but not indestructible. Heat, moisture and time are the main threats, so the material is best kept frozen until the day it ships. On receipt, packages should be opened promptly and vials transferred to appropriate laboratory freezer storage.

Laboratory Storage and Handling of Lyophilized TB-500

The following practices apply to the dry, lyophilized material and to the records kept about it.

• Receiving: Inspect each vial for an intact seal, legible labeling and a dry, uniform powder. Confirm that the product name and any reference number match the Certificate of Analysis on file, and record the date of receipt and storage location.
• Long-Term Storage: Store sealed vials at -20°C, or at -80°C for extended archiving, in a manual-defrost freezer. Frost-free freezers periodically warm to remove ice and expose contents to temperature fluctuations.
• Moisture Control: Keep vials sealed and, where practical, inside a secondary container with desiccant. Lyophilized peptides take up atmospheric moisture readily.
• Oxidation Control: Because TB-500 contains methionine, minimizing exposure to air and light helps limit sulfoxide formation. Keep vials closed and in their carton until needed.
• Opening a Vial: Allow the sealed vial to reach room temperature for 15 to 20 minutes before opening, so that condensation does not form on the cold powder. Minimize the time the vial is open and reseal promptly.
• Weighing: Use a calibrated microbalance with static control for small quantities, and use the net peptide content on the COA to convert between powder mass and peptide mass in analytical calculations.
• Protective Equipment: Wear gloves, a lab coat and eye protection, and weigh fine powders in a draft-shielded enclosure. Hazard and disposal information is provided on our Safety Data Sheets page.
• Recordkeeping and Disposal: Log each opening and the remaining quantity, and dispose of expired or unneeded material through institutional chemical waste procedures.

Consistent storage and documentation practices are fundamental to reproducible data in any laboratory that keeps TB-500 in its inventory.

Frequently Asked Questions (FAQ) for Researchers

Q1: What is the precise difference between endogenous Thymosin Beta-4 and the research peptide TB-500? A: Endogenous Thymosin Beta-4 (Tβ4) is a 43-amino acid peptide produced by cells in most mammalian tissues. The research peptide referred to as TB-500 in this article is material made by solid-phase synthesis that corresponds to the full 43-residue, N-terminally acetylated Tβ4 sequence, with a theoretical average mass of approximately 4963.4 Da. Because some suppliers use the TB-500 name for a shorter fragment, the sequence stated in the documentation should always be checked. Shorter sequences such as the tetrapeptide Ac-SDKP are distinct compounds with their own molecular weights and literature, and they should not be confused with the full-length peptide.

Q2: Why does HPLC purity matter for in-vitro studies? A: HPLC purity indicates how much of the detected material is the intended sequence. The remainder consists of closely related by-products of synthesis, such as truncated or deletion sequences, which can have their own properties. Documenting purity allows a laboratory to state exactly what material it used and makes it possible for others to reproduce the work with comparable material.

Q3: What is the amino acid sequence of TB-500? A: The single-letter amino acid sequence for full-length TB-500 (thymosin beta-4) is: Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES

Q4: How should lyophilized TB-500 be stored? A: Keep lyophilized TB-500 sealed at −20 °C as listed on the product page, protected from light and moisture; avoid repeated freeze–thaw.

Q5: Why is TB-500 N-terminally acetylated? A: Native thymosin beta-4 carries an acetyl group on its N-terminal serine, and synthetic research material reproduces this modification so that its structure corresponds to the native sequence. The acetyl group removes the positive charge of the free N-terminal amine and adds 42 Da to the molecular mass, so it must be included when calculating the theoretical mass used for identity confirmation.

Q6: Is TB-500 the same product as the Wolverine Blend? A: No. TB-500 is a single peptide. The Wolverine Blend is a separate research formulation that combines TB-500 with BPC-157 in one vial. Each product has its own documentation, and the two should be recorded as distinct materials in laboratory inventories and methods sections.

Q7: How does mass spectrometry confirm the identity of a TB-500 sample? A: Mass spectrometry measures the mass-to-charge ratio of ionized peptide molecules. For a peptide of about 5 kDa, electrospray ionization produces a series of multiply charged ions, and software deconvolutes these into a single intact mass. That observed mass is compared with the theoretical value of approximately 4963.4 Da calculated from the acetylated 43-residue sequence. Agreement within the instrument's tolerance confirms that the sample is the correct sequence rather than a fragment, a different peptide or a major impurity.

Q8: Why is endotoxin testing relevant to laboratories that work with cultured immune cells? A: Macrophages and other innate immune cells respond strongly to bacterial endotoxins (lipopolysaccharides) through Toll-like receptor 4 signaling, even at very low concentrations. If any reagent in a cell-based experiment contains endotoxin, that contamination can dominate the readout and confound interpretation. An endotoxin value on the documentation helps the laboratory rule out the peptide preparation as a source of this artifact.

Q9: What does "net peptide content" on a COA mean, and how is it different from purity? A: Purity (by HPLC) describes what proportion of the detected peptide material is the correct, full-length sequence. Net peptide content describes what proportion of the total powder mass is peptide at all; the rest is counter-ions (such as acetate or trifluoroacetate, carried over from purification) and bound water. The two values answer different questions, and both are needed when calculating a precise molar quantity for analytical work.

Q10: What does a peak 16 Da heavier than the expected mass indicate? A: For TB-500, a species 16 Da heavier than the theoretical mass most commonly indicates oxidation of methionine 6 to methionine sulfoxide. Small amounts can form during synthesis, handling or storage. Minimizing exposure to air, light and moisture, and storing the lyophilized powder cold and sealed, limits further oxidation.

Glossary of Technical Terms

• Acetylation: The addition of an acetyl group (CH3CO-), here at the N-terminus of the peptide chain.
• Actin: A highly abundant intracellular protein that forms microfilaments. It is a critical component of the cytoskeleton in eukaryotic cells and is essential for cell shape, motility and division.
• Certificate of Analysis (COA): A document that records the analytical tests performed on a product and confirms that it meets its stated specifications.
• Deconvolution: The computational conversion of a series of multiply charged ions in a mass spectrum into a single neutral molecular mass.
• Endotoxin: A lipopolysaccharide component of the outer membrane of Gram-negative bacteria, measured by the LAL test.
• G-actin / F-actin: Monomeric (globular) actin and filamentous actin, respectively.
• High-Performance Liquid Chromatography (HPLC): An analytical technique used to separate, identify and quantify each component in a mixture. It is the standard method for determining peptide chromatographic purity.
• In-Vitro: Research conducted with cells or biological molecules outside a living organism, for example in test tubes or cell culture dishes.
• Intrinsically Disordered Peptide: A peptide or protein that lacks a stable folded structure in solution.
• Lyophilization: A freeze-drying process that removes water from a product after it is frozen and placed under a vacuum, allowing the ice to change directly from solid to vapor. It is used to preserve perishable materials such as peptides.
• Mass Spectrometry (MS): An analytical technique that measures the mass-to-charge ratio of ions. It is used to confirm the molecular weight and thus the identity of a peptide.
• Methionine Sulfoxide: The oxidized form of methionine, 16 Da heavier than the parent residue.
• Net Peptide Content: The proportion of a lyophilized powder's total mass that is peptide rather than counter-ions and water.
• WH2 Motif: WASP-homology 2, a short actin-binding sequence motif shared by several actin-binding proteins.

References

Hannappel E. Ann N Y Acad Sci. 2007;1112:21-37.

Huff T, Müller CS, Otto AM, Netzker R, Hannappel E. Int J Biochem Cell Biol. 2001;33(3):205-220.

Irobi E, Aguda AH, Larsson M, Guerin C, Yin HL, Burtnick LD, et al. EMBO J. 2004;23(18):3599-3608.

Low TL, Hu SK, Goldstein AL. Proc Natl Acad Sci USA. 1981;78(2):1162-1166.

Safer D, Elzinga M, Nachmias VT. J Biol Chem. 1991;266(7):4029-4032.

Sikiric P, et al. J Physiol Pharmacol. 2013;64(2):177-187.

Smart N, et al. Circ Res. 2011;109(6):661-671.

Disclaimer: All products sold by Excalibur Peptides, including TB-500, are intended for laboratory research purposes only. These materials are not intended for use as food additives, drugs, cosmetics, household chemicals, or other inappropriate applications. The listing of a material on this site does not constitute a license to, or a recommendation for, its use in infringement of any patent. The information presented is for educational and informational purposes only and is not to be misconstrued as an endorsement of any particular use. It is the sole responsibility of the researcher to handle, store, and use these products in a safe and compliant manner, in accordance with all applicable laws and regulations. For all inquiries, please contact our support team at info@excaliburpeptides.com.