title: Conformationally restricted inhibitors of angiotensin converting enzyme: synthesis and computations.
abstract: A series of inhibitors of angiotensin converting enzyme (ACE, dipeptidyl carboxypeptidase, EC 3.4.15.1) is described which addresses certain conformational aspects of the enzyme-inhibitor interaction. In this study the alanylproline portion of the potent ACE inhibitor enalaprilat (2) is replaced by a series of monocyclic lactams containing the required recognition and binding elements. In order to more fully assess the lactam ring conformations and the key backbone angle psi as defined in 3 with respect to possible enzyme-bound conformations, a series of model lactams was investigated with use of molecular mechanics. The results point to a correlation between inhibitor potency (IC50) and the computed psi angle for the lowest energy conformation of the model compounds. Thus the psi angle as defined in 3 is an important determinant in the binding of inhibitors to ACE. The inhibition data in conjunction with the computational data have served to define a window of psi angles from 130 degrees to 170 degrees which seems to be acceptable to the ACE active site.
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril / Q000031:analogs & derivatives / Q000494:pharmacology; D015773:Enalaprilat; D008968:Molecular Conformation; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril; D015773:Enalaprilat