Open AccessComplete amino acid sequence of bovine thymosin beta 4: a thymic hormone that induces terminal deoxynucleotidyl transferase activity in thymocyte populations.
Author(s) -
Teresa L. K. Low,
Shu-Kuang Hu,
Allan L. Goldstein
Publication year - 1981
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.78.2.1162
Subject(s) - thymosin , terminal deoxynucleotidyl transferase , thymocyte , biology , microbiology and biotechnology , peptide sequence , peptide , isoelectric point , biochemistry , amino acid , transferase , tunel assay , antigen , immunology , enzyme , cd8 , gene , apoptosis
The amino acid sequence of thymosin beta 4, a polypeptide isolated from calf thymus, was determined. Thymosin beta 4 is composed of 43 amino acid residues and has a molecular weight of 4982 and an isoelectric point of 5.1. The NH2 terminus of the peptide is blocked by an acetyl group. This molecule induces expression of terminal deoxynucleotidyl transferase (DNA nucleotidylexotransferase, EC 2.7.7.31) in transferase-negative murine thymocytes in vivo and in citro. Thus, it appears that thymosin beta 4 acts on lymphoid stem cells and may control the early stages of the maturation process of thymus-dependent lymphocytes. This peptide is one of several present in thymosin fraction 5 that participates in the regulation, differentiation, and function of thymus-dependent thymocytes.