title: Chemical synthesis of a peptide fragment of thymopoietin II that induces selective T cell differentiation.
abstract: Thymopoietin is a polypeptide hormone of the thymus that consists of a 49 amino acid polypeptide chain of 5562 daltons. A peptide corresponding to positions 29-41 of bovine thymopoietin II was synthesized by the Merrifield solid-phase technique. This peptide was shown to have a purity (correct sequence) of 96% by amino acid and C terminal analyses and by a complete determination of the amino acid sequence by manual Edman degradations. It displayed a selectivity of action similar to that of thymopoietin itself, inducing the differentiation of T lymphocytes but not of complement receptor (CR+) B lymphocytes. Although a number of substances induce the differentiation of both T cells and CR+B cells under the conditions of assay in vitro, only thymopoietin and the synthetic peptide described in this report have been shown to induce the differentiation of T cells selectively. Our data establish that the key residues involved in the active site of thymopoietin are present within a synthetic polypeptide which constitutes a minor portion of the amino acid sequence of thymopoietin. Since this peptide had 3% activity by comparison with thymopoietin, the tertiary structure of thymopoietin may be required for optimal configuration of the active site to produce full biological activity.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects; D001665:Binding Sites; D002454:Cell Differentiation; D004305:Dose-Response Relationship, Drug; D051379:Mice; D008815:Mice, Inbred Strains; D010446:Peptide Fragments / Q000032:analysis / Q000138:chemical synthesis / Q000494:pharmacology; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects; D013947:Thymosin / Q000138:chemical synthesis* / Q000494:pharmacology; D013949:Thymus Extracts / Q000138:chemical synthesis* / Q000494:pharmacology
chemical_list: D010446:Peptide Fragments; D013949:Thymus Extracts; D013947:Thymosin