Isolation of peptides from calf thymus

Abstract

A procedure that minimizes the possibility of proteolytic modification has been developed for the isolation of peptides from calf thymus. Separation of the peptide fraction by reverse phase high performance liquid chromatography revealed the presence of a major peak identified as thymosin β 4 [ Low et al (1981) Proc. Nat. Acad. Sci. USA 78, 1162–1166], but thymosin α 1 [ Low et al (1979) J. Biol. Chem. 254, 981–986] was absent or present in only trace amounts. The absence of thymosin α 1 and other peptides of similar size suggests that their presence in thymosin Fraction 5 may be the result of proteolytic modification of larger thymic peptides or proteins.