Apstatin analogue inhibitors of aminopeptidase P, a bradykinin-degrading enzyme.
Membrane-bound aminopeptidase P (AP-P) participates in the degradation of bradykinin in several vascular beds. We have developed an inhibitor of AP-P called apstatin (1) (N-[(2S, 3R)-3-amino-2-hydroxy-4-phenyl-butanoyl]-L-prolyl-L-prolyl-L-al aninam ide); IC50,human = 2.9 microM. In the rat, apstatin can potentiate the vasodilatory effect of bradykinin, reduce blood pressure in an aortic-coarctation model of hypertension, and reduce cardiac damage and arrhythmias induced by ischemia/reperfusion. In this study, we have determined structure-activity relationships for apstatin analogues as well as for other chemical classes of inhibitors using AP-P isozymes from different sources. The most potent inhibitor was one in which the N-terminal residue of apstatin was replaced with a (2S,3R)-3-amino-2-hydroxy-5-methyl-hexanoyl residue (6, IC50,human = 0.23 microM). The (2R,3S)-analogue of 6 was equipotent with 6 while the (2S,3S)- and (2R,3R)-analogues were considerably less potent. Apstatin analogues lacking the L-alanine or having hydroxyproline in place of the proline in the second position had reduced affinity. Certain thiol-, carboxylalkyl-, and hydroxamate-containing compounds were inhibitory in the low micromolar range. Human cytosolic AP-P isozymes and Escherichia coli AP-P exhibited different inhibitor profiles than mammalian membrane-bound AP-P isozymes. The effects of the compounds on X-Pro dipeptidase (prolidase) and leucyl aminopeptidase are also presented.
Pharmacia and Upjohn, Inc., Kalamazoo, Michigan 49001, USA. Linda.L.Maggiora@am.pnu.com
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Maggiora
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Orawski
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Simmons
D000626:Aminopeptidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000201:enzymology; D001920:Bradykinin / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D004150:Dipeptidases / Q000037:antagonists & inhibitors; D004926:Escherichia coli / Q000737:chemistry; D006801:Humans; D006877:Hydroxamic Acids / Q000737:chemistry / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D007931:Leucyl Aminopeptidase / Q000037:antagonists & inhibitors; D008168:Lung / Q000201:enzymology; D008252:Macaca fascicularis; D009206:Myocardium / Q000201:enzymology; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011480:Protease Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000494:pharmacology; D013552:Swine
C120071:(3-amino-2-hydroxy-5-methylhexanoyl)-prolyl-prolyl-alaninamide; D006877:Hydroxamic Acids; D007527:Isoenzymes; D009842:Oligopeptides; D010455:Peptides; D011480:Protease Inhibitors; D013438:Sulfhydryl Compounds; D000626:Aminopeptidases; D007931:Leucyl Aminopeptidase; C022750:X-Pro aminopeptidase; D004150:Dipeptidases; C022449:proline dipeptidase; C097277:apstatin; D001920:Bradykinin