Solid phase synthesis of thymosin β9

Abstract
Thymosin β9, a 41 residue thymic polypeptide, has been synthesized by a solid phase method. A modification of the low HF method was used to deprotect and cleave the peptide from the resin. Thymosin β9 was then obtained in analytically pure form by a one‐step purification procedure in 32% yield. The activity of thymosin β9 in the terminal deoxynucleotidyl transferase assay was greater than calf thymus fraction 5, but comparable to thymosin β4. In contrast to thymosin α1, neither β4 nor β9 was active in the rosette inhibition assay.