title: [3H]Captopril binding to membrane associated angiotensin converting enzyme.
abstract: [3H]Captopril binding to membrane fractions of rat tissues is saturable and reversible with a KD of 2.4 nM. [3H]Captopril binding and angiotensin converting enzyme measured with hippuryl-L-histidine-L-leucine are distributed in parallel between different tissues and brain regions, with highest levels in the choroid plexus, lung and corpus striatum. Captopril, N-(1(S)-carboxy-3-phenyl-propyl)-L-alanyl-L-proline, N-(1(S)-carboxy-3-phenyl-propyl)-L-lysyl-L-proline, teprotide, thiorphan and S-acetylcaptopril each have similar potencies for inhibition of [3H]captopril binding and of angiotensin converting enzyme. These data strongly indicate that [3H]captopril binds selectively to angiotensin converting enzyme. [3H]Captopril binding evaluation should help clarify the localization and function of angiotensin converting enzyme and assist in defining pharmacologic actions of captopril.
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism; D002216:Captopril / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D011392:Proline / Q000031:analogs & derivatives*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D011392:Proline; D002216:Captopril; D007703:Peptidyl-Dipeptidase A