RES-701-1/endothelin-1 hybrid peptide having a potent binding activity for type B receptor

N-Terminal cyclic peptide of RES-701-1, an endothelin (ET) type B receptor selective antagonist, was chemically combined to C-terminal peptide of ET family. Among a series of the hybrid peptide synthesized, RES-701-1(1–10)/[A15]ET-1(12–21) hybrid peptide possessed both a potent binding activity with an IC50 value of 0.24nM and a selectivity for type B receptor.