Guinea pig eosinophil major basic protein as a potent histamine releaser. (II) Structure-activity relationships of GMBP₁ and GMBP₂

Abstract

Based on the amino acid sequences of GMBP₁ and GMBP₂, several oligopeptides were synthesized and their histamine releasing activity from rat peritoneal mast cells was compared. Basic peptides having more than two amino acids in succession were effective in releasing histamine both in the presence and in the absence of extracellular Ca²⁺, although neutral and acidic peptides were not active. Histamine release caused by the active peptides was more pronounced in the absence of extracellular Ca²⁺ than in the presence of Ca²⁺. From the structure-activity relationships, it is suggested that the histamine releasing activity of these oligopeptides may be dependent not only on the basicity but also on the arrangement of basic amino acids residues, and that hydrophobic amino acids are probably also involved in histamine release.