title: Immuno-regulating peptides, I. Synthesis and structure-activity relationships of thymopentin analogs.
abstract: Seventeen peptides, related to thymopoietin pentapeptide, L-arginyl-L-lysyl-L-aspartyl-L-valyl-L-tyrosine (thymopentin) were synthesized by the stepwise strategy in solution. Of these, L-arginyl-L-lysyl-L-aspartic acid and L-arginyl-L-lysyl-L-aspartyl-L-valine, shortened from the C-terminus of the pentapeptide, exhibit significant immuno-stimulating potencies, exceeding those of thymopentin, both in vitro and in vivo immunological tests. Studies on the structure-activity relationships suggest that the potencial active site of thymopoietins is very sensitive to the N- and C-terminal elongations of the peptide chain. For thymic hormones, an active site carrying cumulative chemical signals is proposed instead of well-defined active centers.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001681:Biological Assay; D007075:Immunoglobulin M / Q000235:genetics; D007202:Indicators and Reagents; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000494:pharmacology; D051381:Rats; D013329:Structure-Activity Relationship; D013946:Thymopoietins / Q000138:chemical synthesis* / Q000494:pharmacology; D013951:Thymus Hormones / Q000138:chemical synthesis*
chemical_list: D007075:Immunoglobulin M; D007202:Indicators and Reagents; D009842:Oligopeptides; D013946:Thymopoietins; D013951:Thymus Hormones