TB-500

TB-500 as catalogued here corresponds to thymosin beta-4 (Tβ4), a 43-residue polypeptide of about 4,963 Da (CAS 77591-33-4). Tβ4 is the most abundant member of the beta-thymosin family in mammalian tissue and is regarded as the main G-actin sequestering peptide, binding actin monomers and holding them out of filaments. A seven-residue actin-binding motif, LKKTETQ (residues 17 to 23), has been mapped within the sequence, and the N-terminal tetrapeptide Ac-SDKP is released from Tβ4 by the enzymes meprin α and prolyl oligopeptidase.

TB-500 in the research literature

Tβ4 has been studied mainly in cell-culture and rodent systems focused on cell migration and vascular signaling. It promoted migration of umbilical vein endothelial cells, and the isolated actin-binding motif reproduced its endothelial migration and aortic-ring sprouting activity at about 50 nM. It also stimulated keratinocyte migration in vitro, and in a rat full-thickness dermal excision model it was associated with increased reepithelialization, collagen deposition and angiogenesis.

In cardiomyocyte cultures Tβ4 formed a complex with PINCH and integrin-linked kinase (ILK), leading to activation of Akt, and after coronary artery ligation in mice it was associated with upregulated ILK and Akt activity.