title: Conversion of porcine big endothelin to endothelin by an extract from the porcine aortic endothelial cells.
abstract: Conversion of porcine big endothelin (big ET) to endothelin (ET) by an extract from cultured porcine aortic endothelial cells was investigated using a radioimmunoassay (RIA) specific for ET and reverse-phase high performance liquid chromatography (RP-HPLC). When big ET was incubated with the extract at an acid pH in the presence of E-64, a cysteine protease inhibitor, the amount of immunoreactive-ET (IR-ET) in the incubation mixture was greatly increased and the optimum pH for this increased reaction was 4.0. The extract-induced increase in IR-ET was completely inhibited by pepstatin-A. These immunoreactive alterations correlated with those in the vasoconstrictor activity. When the incubation mixture of big ET with the cell extract was applied to the RP-HPLC, the IR-ET eluted at the same retention time as seen with synthetic porcine ET. We suggest that a pepstatin-sensitive aspartic protease is involved in the conversion of big ET to ET in vascular endothelial cells.
authors.affiliation: Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumura
authors.forename: R
authors.initials: R
authors.lastname: Ikegawa
authors.forename: M
authors.initials: M
authors.lastname: Takaoka
authors.forename: S
authors.initials: S
authors.lastname: Morimoto
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D019332:Endothelin-1; D016232:Endothelins; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D010436:Pepstatins / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D011863:Radioimmunoassay; D013552:Swine
chemical_list: D019332:Endothelin-1; D016232:Endothelins; D010436:Pepstatins; D010455:Peptides; D011498:Protein Precursors; C014195:Streptomyces pepsin inhibitor; C031375:pepstatin