Thymulin is a nonapeptide — a chain of nine amino acids — with the sequence pyroglutamyl-alanyl-lysyl-seryl-glutaminyl-glycyl-glycyl-seryl-asparagine (Pyr-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn). It was first isolated and characterized in 1977 from thymic epithelial cells in the thymus gland. Without its zinc cofactor, the peptide has a molecular weight of approximately 858 g/mol with the formula C₃₃H₅₄N₁₂O₁₅.

What distinguishes thymulin from other thymic peptides is that it requires a zinc ion (Zn²⁺) to adopt its characteristic three-dimensional fold. The zinc binds to specific residues in the peptide chain, and without it the molecule remains in an unfolded state. It is supplied as a white lyophilized powder, soluble in water, and should be stored refrigerated at 2–8 °C. This product is strictly for research purposes only.

PubChem Reference: View compound profile on NIH PubChem