Chemical characterization of thymosin beta 4

As part of our ongoing investigations on the endocrine thymus, we have isolated and purified to homogeneity a hormone-like peptide which we have termed thymosin beta 4. Thymosin beta 4 has Mr = 4982 and an isoelectric point of 5.1. The complete amino acid sequence of this polypeptide has been establ...

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Bibliographic Details
Published in:The Journal of biological chemistry 1982-01, Vol.257 (2), p.1000-1006
Main Authors: Low, T L, Goldstein, A L
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Cattle
Cyanogen Bromide
Isoelectric Focusing
Molecular Weight
Peptide Fragments - analysis
Spleen
Thermolysin
Thymosin - analogs & derivatives
Thymus Hormones
Trypsin
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Summary:As part of our ongoing investigations on the endocrine thymus, we have isolated and purified to homogeneity a hormone-like peptide which we have termed thymosin beta 4. Thymosin beta 4 has Mr = 4982 and an isoelectric point of 5.1. The complete amino acid sequence of this polypeptide has been established by automated Edman degradation as well as by manual sequence analysis. Thymosin beta 4 is composed of 43 amino acid residues with acetylserine at the NH2 terminus. This molecule induces expression of terminal deoxynucleotidyl transferase in transferase-negative murine thymocytes in vivo and in vitro. It also exhibits ability to inhibit the migration of macrophages. Comparison of the sequence of thymosin beta 4 to other thymic hormones or other published protein sequences does not reveal any statistically significant relationship. Two helical regions were identified in the structure using data for prediction of protein conformation. It is proposed that thymosin beta 4 is one of the biologically active peptides present in thymosin fractions 5 and 5A which participate in the regulation, differentiation, and function of thymus-derived lymphocytes and may also act directly or indirectly on macrophages and perhaps other cells involved in cell-mediated immunity.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(19)68299-2