title: Angiotensin converting enzyme activity in human serum: relationship to enzyme inhibitor in vivo and in vitro.
abstract: Quantitative relationships between angiotensin converting enzyme activity in human serum and concentration of an enzyme inhibitor, the active diacid metabolite of MK-421 [N-(S-1-carbethoxy-3-phenylpropyl)-S-alanyl-S-proline maleate], were defined. Dose-response curves were generated in vitro by adding the diacid metabolite (DM) to serum (ID50 = to 6x10-9 M); l0-15% of initial activity was nonsuppressible. DM an converting enzyme activity were also measured in serum from hypertensive subjects receiving oral MK-421. The dose-response curve for serum samples following single doses of MK-421 (ID50 = 6x10-9M), was similar to curves generated in vitro while the curve for sample following chronic therapy suggested a small decrease in inhibitory potency.
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors; D004151:Dipeptides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004656:Enalapril; D006801:Humans; D066298:In Vitro Techniques; D007703:Peptidyl-Dipeptidase A / Q000097:blood*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004151:Dipeptides; D004656:Enalapril; D007703:Peptidyl-Dipeptidase A