Thymosin beta 10, a new analog of thymosin beta 4 in mammalian tissues

A new analog of thymosin β 4 has been isolated from tissues of several mammalian species. This peptide, designated thymosin β 10 , is composed of 42 amino acid residues and shows 75% sequence homology with thymosin β 4 . It occurs together with thymoxin β 4 in a variety of tissues including spleen, liver, and thymus and also in several cultured cell lines. In the spleen of rat, mouse, cat, and man, the new peptide accounts for approximately 0.02% by weight of the total protein. In the calf it is replaced by another homologous peptide, designated thymosin β 9 , whose structure has been reported.