Affinity enhancement of complementary peptide recognition.

A peptide hydropathically complementary to Big Endothelin [Big ET] residues 16-29 has been synthesized in a multimeric form starting from an octadentate polylysine core, essentially in a way similar to the procedure used for the production of multiple antigenic peptides [MAP's]. Interaction between the multimeric complementary peptide [8 delta ET] and the Big ET fragment 16-32 containing the target complementary region, also synthesized in a multimeric form [8ET], was evaluated by analytical high performance affinity chromatography and solid phase binding assays. While the binding interaction between the monomerics peptide pair was in the micromolar range, the recognition between the corresponding multimeric form was characterized by enhanced binding affinity of at least two orders of magnitude. In solution, complex formation between multimeric complementary peptide and target Big ET sequence in the monomeric and multimeric form was accompanied by precipitation at concentrations higher than 0.5 mg/mL and 0.1 mg/mL, respectively. Polyclonal antibodies raised against the multimeric target sequence recognized multimeric and monomeric ET target sequences with binding affinities similar to binding affinities exhibited by the multimeric complementary peptide. Multimerization of hydropathically complementary peptides could provide an improved opportunity to measure and thus probe quantitative binding properties of complementary peptides.