Diastereoselective solution and multipin-based combinatorial array synthesis of a novel class of potent phosphinic metalloprotease inhibitors

The solution-phase synthesis and resolution of new phosphinopeptidic building blocks containing a triple bond was realized in high yields and optical purities (units 3a-d). The absolute configuration of the target compounds was unambiguously established by NMR studies. A post-assembly diversification strategy of these blocks was developed through 1,3-dipolar cycloaddition of a variety of in situ prepared nitrile oxides. This strategy led to the rapid and efficient diastereoselective preparation of a novel class of isoxazole-containing phosphinic peptides (peptides 5a-i). Solid-phase version of this strategy was efficiently achieved on multipin solid technology, by developing a new protocol for the coupling of P-unprotected dipeptidic blocks with solid supported amino acids in a quantitative and diastereoselective manner. Optimization of dipolar cycloadditions onto pin-embodied phosphinic peptides allowed the convenient preparation of this new class of pseudopeptides. The crude phosphinic peptides (9a-k) were obtained in high yields and purity as determined by RP-HPLC. Inhibition assays of some of these peptides revealed that they behave as very potent inhibitors of MMPs, outmatching previously reported phosphinic peptides, in terms of potency (Ki in the range of few nM)

Phosphinic peptides: Synthetic approaches and biochemical evaluation as Zn-metalloprotease inhibitors

Over the course of the last decades, phosphinic peptides have emerged as an extremely important class of Zn-metalloprotease inhibitors. The intense interest in these compounds in the field of medicinal chemistry reflects a conjunction of synthetic advances and ideal physicochemical and biochemical properties. Among the latter, the optimal tetrahedral structure of phosphinic acid moiety, which perfectly fills the requirements of transition state theory, clearly defines the mechanistical frame of their function as metalloprotease inhibitors (transition state analogues, TSA). In particular, phosphinic peptides are peptidic isosters containing a chemically stable phosphinic acid moiety which mimics the transition state tetrahedral geometry of a scissile peptide bond during enzymatic hydrolysis. Moreover, the ionic interactions of phosphinic oxyanion with catalytic Zn2+ combined with the substrate-like primary interactions of pseudopeptidic backbone with enzyme's active site, can aid the rationalization of the design and development of potent and selective Zn-protease inhibitors. In these review, we aim to resume the major achievements in this field over the last decades. In the first part, the fundamental principles of phosphinopeptidic chemistry, as these have been established by the pioneers of the field, as well as the synthesis of first-generation inhibitors are presented. In the second part, accounting as a turning point the introduction of SPPS and combinatorial practices in the field, a comprehensive description of all the recent synthetic novelties as well as the outstanding applications of phosphinopeptidic derivatives in enzymatic, biochemical and crystallographic studies is attempted. © 2004 Bentham Science Publishers Ltd

Phosphinic peptides as zinc metalloproteinase inhibitors

Solid-phase synthesis of phosphinic peptides was introduced 10 years ago. A major application of this chemistry has been the development of potent synthetic inhibitors of zinc metalloproteases. Specific properties of the inhibitors produced in recent years are reviewed, supporting the notion that phosphinic pseudo-peptides are useful tools for studying the structural and functional biology of zinc proteases

Future challenges facing the development of specific active-site-directed synthetic inhibitors of MMPs

Despite a deep knowledge on the 3D-structure of several catalytic domains of MMPs, the development of highly specific synthetic active-site-directed inhibitors of MMPs, able to differentiate the different members of this protease family, remains a strong challenge. Due to the flexible nature of NIMP active-site, the development of specific NIMP inhibitors will need to combine sophisticated theoretical and experimental approaches to decipher in each MMP the specific structural and dynamic features that can be exploited to obtain the desired selectivity. (c) 2004 Elsevier SAS. All rights reserved

Development of selective inhibitors and substrate of matrix metalloproteinase-12

Four phosphinic peptide libraries with compounds having the general formula p-Br-Ph-(PO2-CH2)-Xaa′-Yaa′-Zaa′- NH2 have been prepared and screened against 10 matrix metalloproteinases (MMPs). We identified two phosphinic peptides with Ki values of 0.19 and 4.4 nM toward MMP-12 (macrophage elastase) that are more than 2-3 orders of magnitude less potent toward the other MMPs tested. These highly selective MMP-12 inhibitors contain a Glu-Glu motif in their Yaa′-Zaa′ positions. Incorporation of this Glu-Glu motif into the sequence of a nonspecific fluorogenic peptide cleaved by MMPs provides a highly selective substrate for MMP-12. A model of one of these inhibitors interacting with MMP-12 suggests that the selectivity observed might be due, in part, to the presence of two unique polar residues in MMP-12, Thr239 and Lys 177. These MMP-12-selective inhibitors may have important therapeutic applications to diseases in which MMP-12 has been suggested to play a key role, such as in emphysema, atherosclerosis, and aortic abdominal aneurysm. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc