A selective reversible azapeptide inhibitor of human neutrophil proteinase 3 derived from a high affinity FRET substrate

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• 作者：Christophe Epinette^a ; Cé ; cile Croix^b ; Lucie Jaquillard^c ; Sylvain Marchand-Adam^a ; ^d ; Christine Kellenberger^e ; Gilles Lalmanach^a ; Martine Cadene^c ; Marie-Claude Viaud-Massuard^b ; Francis Gauthier^a ; Brice Korkmaz^a ; ^{brice.korkmaz@inserm.fr}
• 关键词：PR3 ; proteinase 3 ; HNE ; human neutrophil elastase ; CG ; cathepsin G ; NSPs ; neutrophil serine proteases ; ¦Á1-PI ; alpha-1-antitrypsin ; Abz ; ortho-aminobenzoic acid ; (nor)V/(nor)Val ; norValine ; ANCAs ; anti-neutrophil cytoplasmic antibodies ; FRET ; fluorescence
• 刊名：Biochemical Pharmacology
• 出版年：2012
• 出版时间：15 March 2012
• 年：2012
• 卷：83
• 期：6
• 页码：788-796
• 全文大小：1143 K

文摘

The biological functions of human neutrophil proteinase 3 (PR3) remain unclear because of its close structural resemblance to neutrophil elastase and its apparent functional redundancy with the latter. Thus, all natural inhibitors of PR3 preferentially target neutrophil elastase. We have designed a selective PR3 inhibitor based on the sequence of one of its specific, sensitive FRET substrates. This azapeptide, azapro-3, inhibits free PR3 in solution, PR3 bound to neutrophil membranes, and the PR3 found in crude lung secretions from patients with chronic inflammatory pulmonary diseases. But it does not inhibit significantly neutrophil elastase or cathepsin G. Unlike most of azapeptides, this inhibitor does not form a stable acyl-enzyme complex; it is a reversible competitive inhibitor with a K_i comparable to the K_m of the parent substrate. Low concentrations (60 ¦ÌM) of azapro-3 totally inhibited the PR3 secreted by triggered human neutrophils (200,000 cells/100 ¦ÌL) and the PR3 in neutrophil homogenates and in lung secretions of patients with lung inflammation for hours. Azapro-3 also resisted proteolysis by all proteases contained in these samples for at least 2 h.