For research use only. Not for human or veterinary consumption. Not FDA-approved for the diagnosis, treatment, cure, or prevention of any disease.
TB-500 is a synthetic analog of Thymosin β4 (Tβ4), a naturally occurring 43-amino acid peptide first isolated from calf thymus extract in the 1960s. With the molecular formula C₂₁₂H₃₅₀N₅₆O₇₈S, a molecular weight of 4,963.49 g/mol, and CAS number 77591-33-4, TB-500 represents one of the most widely studied actin-binding peptides in preclinical research literature.
Molecular Structure and Biochemical Identity
Thymosin β4 belongs to the β-thymosin family — a group of low-molecular-weight proteins with a conserved actin-binding domain. The synthetic TB-500 sequence reproduces the core Tβ4 structure and retains the Wasp homology domain 2 (WH2) motif responsible for G-actin (globular actin) sequestration. The actin cytoskeleton is central to cell motility, morphology, division, and intracellular signaling — making TB-500 a focus of preclinical research across multiple model systems.
TB-500 is supplied by Peptrio as a lyophilized powder, analytically verified to ≥99% purity by HPLC and confirmed by LC-MS. Each 5mg vial ships with a batch-specific Certificate of Analysis from an ISO/IEC 17025-accredited third-party laboratory.
Regulatory Status
TB-500 is classified as a Category 2 substance by the FDA’s Bulk Drug Substances for Compounding Under Section 503B of the Federal Food, Drug, and Cosmetic Act. This classification reflects ongoing evaluation; it does not constitute FDA approval for any indication. TB-500 is supplied by Peptrio exclusively under the Research Use Only (RUO) framework and is not intended for human or veterinary use.
Actin-Sequestration Research
The primary mechanistic interest in Thymosin β4 analogs centers on G-actin sequestration. Huff et al. (2001) characterized the 1:1 molar binding of Tβ4 with G-actin, demonstrating that the peptide’s C-terminal actin-binding segment (LKKTET) is critical for this interaction. In vitro studies have used TB-500 to examine F-actin assembly dynamics, lamellipodia formation, and directional cell migration in various cell line models. These actin-binding properties have made TB-500 a useful tool for dissecting the role of G-actin availability in cytoskeletal regulation.
Angiogenesis and Endothelial Cell Models
A substantial body of preclinical work has examined Thymosin β4 in angiogenesis contexts. In vitro studies using human umbilical vein endothelial cells (HUVECs) have investigated whether Tβ4 analogs modulate endothelial cell migration, tube formation, and proliferation. Goldstein AL et al. (2012; PMID: 21931897) reviewed multifunctional roles of Thymosin β4, noting its interaction with actin, PINCH-1, and integrin-linked kinase (ILK) in endothelial and other cell models.
Cardiac and Myocardial Research Models
Rossdeutsch et al. (2013; PMID: 23426972) investigated the role of Tβ4 in progenitor cell activation and epicardial cell behavior in murine cardiac models. Additional in vitro and murine model studies have examined Tβ4 analog effects on cardiomyocyte survival signaling under oxidative stress conditions, and whether epicardially-derived cell populations respond to Tβ4 stimulation in differentiation assays.
Corneal Epithelial Cell Models
In vitro studies using corneal epithelial cell lines have investigated whether Tβ4 analogs modulate cell migration in scratch-wound assays. Sosne et al. have published multiple studies examining Thymosin β4 in corneal cell models, with mechanistic interest in anti-inflammatory properties and NFκB signaling pathway interactions in cell culture systems. This body of work represents preclinical in vitro data only.
Analytical Specifications — Peptrio TB-500 5mg
| Parameter | Specification |
|---|---|
| Molecular formula | C₂₁₂H₃₅₀N₅₆O₇₈S |
| Molecular weight | 4,963.49 g/mol |
| CAS number | 77591-33-4 |
| Purity | ≥99% (HPLC verified) |
| Identity confirmation | LC-MS |
| Form | Lyophilized powder, 5mg vial |
| Storage | −20°C, protected from light and moisture |
| CoA | Batch-specific, ISO/IEC 17025-accredited lab |
Every vial of TB-500 from Peptrio ships with a batch-specific Certificate of Analysis from an independent ISO/IEC 17025-accredited laboratory. The CoA reports peptide identity by LC-MS, purity by HPLC (≥99%), and full lot traceability. Documentation available on request at peptrio.com.
For research use only. Not for human or veterinary consumption. Not FDA-approved for the diagnosis, treatment, cure, or prevention of any disease or condition. Researchers are responsible for verifying all applicable regulations prior to ordering.