Thymosins are a group of low molecular weight acidic peptides isolated from the original factor thymosin fraction 5 (TF5) extracted from the bovine thymus by AL Goldstein and colleagues. At least 30 different peptides can be identified by isoelectric focusing of TF5, including thymosin α1 (Tα1), β4 (Tβ4), and MB35[1].
