Development of Highly Potent and Selective Phosphinic Peptide Inhibitors of Zinc Endopeptidase 24-15 Using Combinatorial Chemistry

Abstract

This new inhibitor should be useful in assessing the contribution of this proteolytic activity in the physiological inactivation of neuropeptides known to be hydrolyzed, at least in vitro, by endopeptidase 24-15. Our study also demonstrates that the combinatorial chemistry approach leading to the development of phosphinic peptide libraries is a powerful strategy for discovering highly potent and selective inhibitors of zinc metalloproteases and should find a broader application in studies of this important class of enzymes.The endopeptidase 24-15 (EC 3.4.24.15) 1 belongs to the zinc metalloprotease family (1) and resembles a peptidase previously purified from rabbit brain by Camargo et al. (2). Later, endopeptidase 24-15 was named thimet oligopeptidase with respect to the thiol and metal dependence of its catalytic activity (3-5). Molecular cloning of the cDNA of endopeptidase 24-15 revealed a HEXXH motif, which characterizes peptidases belonging to this family, and a cysteine residue, lying on the C-terminal side of the second histidine of the zinc binding motif (6). This cysteine residue has been proposed to be responsible for activation of the enzyme by 2-mercaptoethanol or dithiothreitol, as well as for inhibition of the enzyme activity by thiol reactive reagents (6).24-15 displays several biochemical and physicochemical properties (for a review, see Ref. 7) in common with another zinc-containing metallopeptidase, endopeptidase . Interestingly, these two peptidases have the ability to hydrolyze numerous bioactive or synthetic peptides at the same cleavage site, suggesting that they have a closely related active site (7-9).We previously reported that phosphodiepryl03, a phosphonamide peptide, acts as a potent mixed inhibitor of 24-15 and 24-16, with K i values in the nanomolar range (10). This inhibitor was shown to be unable to block the activity of several other zinc peptidases such as endopeptidase 24-11, angiotensin-converting enzyme, aminopeptidase M, leucine aminopeptidase, and carboxypeptidases A and B. We particularly studied the effect of this inhibitor in vivo on the neurotensin catabolism, since we previously established that 24-15 and 24-16 participated in vitro in the inactivation of this neuropeptide (11,12). We established that phosphodiepryl03 prevented neurotensin degradation in vivo in vascularly perfused dog ileum (13). More recently, several phosphodiepryl03 analogues were also proved to be potent but still acting as mixed inhibitors of

Synthetic inhibitors of endopeptidase EC 3.4.24.15: potency and stability in vitro and in vivo

“…A bulky hydrophobic residue in the PI position apparently interferes with cleavage by NEP, as noted for phenylalanine by Pozsgay et al (1986). Likewise, cleavage of the D-alanine analogue was also markedly reduced (data not shown), in keeping with the stereospecificity of NEP (Hersh & Morihara, 1986 (Jiracek et al, 1995). No data concerning their stability in vivo are yet available; however, as they are peptide-based, they may still be susceptible to proteolytic degradation.…”

Association of aminopeptidase N and endopeptidase 24.15 inhibitors potentiate behavioral effects mediated by nociceptin/orphanin FQ in mice

“…administration of the exogenous heptadecapeptide in the motor activity test was observed (Figs. 2 and 3) in the presence of the association of the aminopeptidase inhibitor, bestatin and the selective endopeptidase 24.15 inhibitor, Ζ-^^ΡΙιεΨ-(P0 2 CH 2 )(L,D)Ala-Arg-Phe [23]. On the other hand, due to the complementary role of endopeptidase 24.15 and aminopeptidase in the nociceptin/orphanin FQ metabolism [16], selective inhibition of only one of these peptidases did not give a significant effect (Fig.…”

Development and characterization of novel potent and stable inhibitors of endopeptidase EC 3.4.24.15

“…So far, the most potent and selective inhibitor of EP24.15 reported is the tetrapeptide Z-(,)Phe(PO # CH # )(,)Ala-ArgPhe [9]. This compound, which incorporates a phosphinic acid, has a K i for EP24.15 of 0.16 nM and is more than three orders of magnitude less potent towards EP24.16 (K i 530 nM).…”

“…Although other peptide-based specific inhibitors of EP24.15 have been reported [9] and preliminary studies with whole brain homogenates suggest stability (F. Checler [2]. The specific quenched fluorescent substrate (QFS) 7-methoxycoumarin-4-acetyl-ProLeu-Gly-Pro--Lys-(2,4-dinitrophenyl) was synthesized by AUSPEP (Parkville, Victoria, Australia).…”