A Cyclic Angiotensin Antagonist: angiotensin II

Article abstract of DOI:10.1021/jm00369a030

1,8>angiotensin II has been synthesized by the solid-phase method and purified by carboxymethylcellulose chromatography and reversed-phase HPLC.Treatment of this peptide with iodine gave the cyclic octapeptide 1,8>angiotensin II, which was isolated by Sephadex G-25 chromatography and reversed-phase HPLC.Comparison of the circular dichroism spectra of the open-chain and cyclic peptides, respectively, demonstrated the existence of a disulfide bond with right-handed chirality in the cyclic peptide.In the isolated rat uterus assay, theopen-chain peptide was found to be a potent antagonist of angiotensin II, having approximately 10percent of the activity of 1,Ile⁸>angiotensin II, and the cyclic peptide had about 10percent of the antagonist potency of its open-chain synthetic precursor.