TB500 peptide, CAS 885340-08-9, thymosin β4 fragment, 99% HPLC, white lyophilized powder, for laboratory research use only.

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1. Basic Chemical Properties and Molecular Structure of TB-500

TB-500 (also often written as TB500) is a synthetic bioactive peptide fragment derived from thymosin β-4 (Tβ4). Tβ4 is a naturally occurring 43-amino acid polypeptide widely distributed in mammalian tissues, cells, and body fluids. Currently, the TB-500 circulating in the global biochemical research market refers to the N-terminal active fragment of natural thymosin β-4, with the amino acid sequence: acetyllysine-lysine-threonine-glutamic acid-threonine-glutamine (Ac-LKKTETQ). Its CAS registry number is 885340-08-9, which differs from the full-length thymosin β-4 (CAS: 77591-33-4).

Its basic physicochemical parameters are core reference standards for laboratory procurement and experimental configuration. TB-500 has the molecular formula C36H66N14O16 and a precisely calculated molecular weight of 889.02 Da. The finished product is a white or off-white lyophilized crystalline powder, sealed in sterile glass vials using vacuum lyophilization technology. This lyophilization method effectively avoids peptide degradation caused by high temperature, high humidity, and oxidation during transportation and long-term storage. TB-500 exhibits excellent solubility: it dissolves rapidly in sterile distilled water, phosphate-buffered saline (PBS), and physiological saline, greatly facilitating the preparation of experimental products for cell culture, in vitro biochemical analysis, and animal model drug administration in the laboratory.

Our factory uses high-performance liquid chromatography (HPLC) to strictly control product purity, achieving a purity standard of 98% to 99%. Each batch of TB-500 comes with a complete Certificate of Analysis (COA), including an HPLC purity report, moisture content, heavy metal residue, microbial limit test, endotoxin test, and residual solvent test, fully complying with international quality standards for biochemical reagents used in laboratory research. Standard packaging is available in 5mg and 10mg sterile vials. We also offer bulk raw material powder in aluminum foil vacuum bags for large academic institutions and biomedical laboratories, and can provide customized packaging solutions upon request. Recommended storage conditions are -20°C, protected from light and sealed; repeated freeze-thaw cycles should be avoided to maintain the structural stability and bioactivity of the peptide.

2. Biosynthetic Source and Molecular Mechanism of Action

Natural thymosin β4 (Tβ4) was initially isolated from bovine thymus tissue in the 1960s. Subsequent biomedical research confirmed that this endogenous peptide participates in multiple core cellular physiological processes in organisms. However, the full-length Tβ4 molecule is relatively large, metabolized and absorbed slowly, and involves complex signaling pathways in experimental systems. Biomedical researchers discovered that a seven-amino acid fragment truncated from the proximal end of Tβ4 retains almost all the key bioactive domains of the full-length peptide, while possessing advantages such as smaller molecular size, higher stability, lower degradation rate, and easier artificial chemical synthesis—this optimized fragment was named TB-500 and is used for standardized research applications. The core molecular mechanism of TB-500 lies in regulating actin polymerization, a fundamental biological pathway for cell migration, cytoskeleton construction, and tissue remodeling. Actin is a major protein structure constituting the cytoskeleton; the dynamic balance between monomeric globular actin (G-actin) and filamentous actin (F-actin) directly determines cell motility, morphological changes, and extracellular matrix remodeling. TB-500 specifically binds to intracellular G-actin monomers, effectively inhibiting excessive actin aggregation and stabilizing the reversible cycle between G-actin and F-actin. This regulatory effect releases the motility potential of various somatic cells, including fibroblasts, endothelial cells, keratinocytes, and immune inflammatory cells.

In addition to regulating actin, TB-500 also participates in multiple intracellular signaling pathways. It can upregulate…