Conformationally constrained renin inhibitory peptides: .gamma.-lactam-bridged dipeptide isostere as conformational restriction

Abstract
A model of the conformation of the enzyme-bound inhibitor of human renin suggested the possibility of a .gamma.-lactam conformational restriction of the P2-P3 site. Synthetic routes to these .gamma.-lactam peptide isosteres and their incorporation into potential renin inhibitors are described. Peptide VIa,b with a .gamma.-lactam confornational constraint and a hydroxyethylene isostere at the cleavage site inhibited human plasma renin with an IC50 value of 6.5 nM. The flexibility of these eyntheses should make available a number of potential enzyme inhibitors with this structural feature for the study of enzyme-bound conformers.