title: Accumulation of pepstatin in cultured endothelial cells and its effect on endothelial processing.
abstract: Aspartic acid proteases have been implicated in the processing of ET-1(1-39) to ET-1(1-21). To further understand the role of this class of enzymes in ET-1 synthesis, cultured vascular endothelial cells were incubated with pepstatin, and the accumulation of the inhibitor and its effect on the processing of ET-1(1-39) was examined. Pepstatin accumulated in the cells in a time-dependent manner, to a concentration (greater than 10(-7) M) sufficient to inhibit aspartic acid proteases. Pepstatin did not alter the ratio of ET-1(1-21) to ET-1(1-39), nor did it affect the rate of secretion of either peptide. When endothelial cells were incubated with phosphoramidon under identical conditions, the secretion of ET-1(1-21) was significantly reduced with a concomitant increase in the secretion of ET-1(1-39). These results suggest that the processing of ET-1(1-39) does not involve a pepstatin-sensitive aspartic acid protease, and that the enzyme responsible for generating ET-1(1-21) is sensitive to phosphoramidon.
authors.affiliation: Protein Chemistry Group, Unigene Laboratories, Inc., Fairfield, NJ 07004.
authors.forename: P P
authors.initials: PP
authors.lastname: Shields
authors.forename: T A
authors.initials: TA
authors.lastname: Gonzales
authors.forename: D
authors.initials: D
authors.lastname: Charles
authors.forename: J P
authors.initials: JP
authors.lastname: Gilligan
authors.forename: W
authors.initials: W
authors.lastname: Stern
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism; D001692:Biological Transport; D002402:Cathepsin D / Q000037:antagonists & inhibitors; D002417:Cattle; D002460:Cell Line; D016232:Endothelins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D006020:Glycopeptides / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D009842:Oligopeptides; D010436:Pepstatins / Q000378:metabolism* / Q000494:pharmacology; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D013379:Substrate Specificity; D013820:Thermolysin / Q000037:antagonists & inhibitors
chemical_list: D016232:Endothelins; D006020:Glycopeptides; D009842:Oligopeptides; D010436:Pepstatins; D016282:Aspartic Acid Endopeptidases; D002402:Cathepsin D; D013820:Thermolysin; C008890:phosphoramidon