TB-500 – Research Peptide

What TB-500 is Thymosin beta-4 is a 43-residue peptide present in almost every mammalian cell type and the main G-actin sequestering molecule in the cytosol. In the research-supply market the name “TB-500” is applied both to the full-length protein and to a seven-residue actin-binding fragment; the two are chemically distinct and are not interchangeable. Mechanism Binds monomeric G-actin through the conserved LKKTETQ motif, holding a reserve pool that buffers filament assembly. This places it upstream of cytoskeletal remodelling, and by extension of cell migration, wound closure and endothelial organisation in culture. Where it appears in research G-actin sequestration and polymerisation kinetics Cell migration and cytoskeletal dynamics Corneal and dermal wound-model research Cardiac cell migration studies History First isolated from calf thymus in 1981 by Teresa Low and Allan Goldstein, who were characterising thymic peptides. Its role as an actin-sequestering protein was established later in the decade and reframed it from an immune factor to a cytoskeletal one.