Do β-Thymosins Play a Role in Human Nephrogenesis?

β-Thymosins are a family of ubiquitous peptides with a molecular mass of about 5 kDa and with a sequence of 40–44 amino acid residues. The name thymosin derives from the first isolation of these peptides from calf thymus in 1966 by Goldstein et al. (Proc Natl Acad USA 56:1010–17) among other lymphocytopoietic factors. Thymosins are subdivided into three main groups according to their different isoelectric points: α-thymosins, β-thymosins, and γ-thymosins with a pH below 5.0, between 5.0 and 7.0, and above 7.0, respectively. Hannappel and coworkers first isolated Tβ4 from vertebrate’s and invertebrate’s cells through different schemes of purification. More than 15 β-thymosins were described but Tβ4 is known to be the most expressed peptide in mammalians including humans.