title: Endothelin-converting enzyme: substrate specificity and inhibition by novel analogs of phosphoramidon.
abstract: Endothelin converting enzyme was partially purified by detergent extraction and ion exchange chromatography from porcine aortic endothelial cells. This kinetically homogeneous preparation catalyzes the hydrolysis of porcine big endothelin-1 to endothelin-1 with a pH optimum of 7. Human big endothelins-1, -2, and -3 are also hydrolyzed, but at progressively lower rates. Fragments of big porcine endothelin-1 comprising residues 16-39 and 16-29 are good substrates, but additional C-terminal truncations are devoid of substrate activity. Endothelin converting enzyme is characteristically inhibited by phosphoramidon and other metalloproteinase inhibitors including EDTA, o-phenanthroline, and diethylpyrocarbonate, but not by inhibitors of other classes of proteases or thiorphan. The inhibition by phosphoramidon is competitive with big porcine endothelin-1 suggestive of a common binding site for substrate and inhibitor. A number of novel analogs of phosphoramidon were synthesized by modifying various regions of the molecule and tested for inhibitory activity. The most potent of these, a methylphosphonic acid, has an IC50 of 0.05 microM.
authors.affiliation: Department of Medicinal Chemistry, Research and Development Division, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Keller
authors.forename: C P
authors.initials: CP
authors.lastname: Lee
authors.forename: A E
authors.initials: AE
authors.lastname: Fenwick
authors.forename: S T
authors.initials: ST
authors.lastname: Atkinson
authors.forename: J D
authors.initials: JD
authors.lastname: Elliott
authors.forename: W E
authors.initials: WE
authors.lastname: DeWolf
mesh_terms: D000818:Animals; D001011:Aorta; D016282:Aspartic Acid Endopeptidases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000072396:Endothelin-Converting Enzymes; D016232:Endothelins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006020:Glycopeptides / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases; D015394:Molecular Structure; D011480:Protease Inhibitors / Q000494:pharmacology*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013552:Swine
chemical_list: D016232:Endothelins; D004791:Enzyme Inhibitors; D006020:Glycopeptides; D011480:Protease Inhibitors; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes; C008890:phosphoramidon