title: Angiotensin IV displays only low affinity for native insulin-regulated aminopeptidase (IRAP).
abstract: Radioligand binding studies revealed that Ang IV binds to insulin-regulated aminopeptidase (IRAP)/'AT(4)  receptors' with high affinity. Yet, as these experiments were routinely carried out in the presence of chelators, only the catalytic zinc-depleted apo-form of IRAP was labelled. While the chelators remove the catalytic zinc from IRAP and protect Ang IV from proteolytic degradation, the aminopeptidase N selective inhibitor '7B' only exerts the latter effect. By using 7B along with the new stable Ang IV-analog [(3) H]AL-11, we here show that the native enzyme is only a low-affinity target for Ang IV.
authors.affiliation: Research Group of Experimental Pharmacology, Department of Molecular and Biochemical Pharmacology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Heidi
authors.initials: H
authors.lastname: Demaegdt
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: De Backer
authors.forename: Aneta
authors.initials: A
authors.lastname: Lukaszuk
authors.forename: Géza
authors.initials: G
authors.lastname: Tóth
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Szemenyei
authors.forename: Dirk
authors.initials: D
authors.lastname: Tourwé
authors.forename: Georges
authors.initials: G
authors.lastname: Vauquelin
mesh_terms: D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000378:metabolism; D000818:Animals; D018826:CD13 Antigens / Q000037:antagonists & inhibitors / Q000378:metabolism; D016466:CHO Cells; D002460:Cell Line; D002614:Chelating Agents / Q000494:pharmacology*; D006224:Cricetinae; D003412:Cricetulus; D010122:Cystinyl Aminopeptidase / Q000378:metabolism*; D051379:Mice; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D011869:Radioligand Assay; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D015032:Zinc / Q000737:chemistry
chemical_list: C573240:2-benzyl-3-(hydroxy(1'-aminoethyl)phosphinyl)propanoyltyrosine; D002614:Chelating Agents; D009943:Organophosphorus Compounds; D000804:Angiotensin II; C012877:angiotensin II, des-Asp(1)-des-Arg(2)-Ile(5)-; D014443:Tyrosine; D018826:CD13 Antigens; D010122:Cystinyl Aminopeptidase; C105964:leucyl-cystinyl aminopeptidase; D015032:Zinc