Abstract
Dipeptidyl (acyloxy)methyl ketones (AOMKs) have been identified as mechanism-based inhibitors of certain cysteine proteases. These compounds are also inhibitors of the integral membrane proteins Rce1p and Ste24p, which are proteases that independently mediate a cleavage step associated with the maturation of certain isoprenylated proteins. The enzymatic mechanism of Rce1p is ill-defined, whereas Ste24p is a zinc metalloprotease. Rce1p is required for the proper processing of the oncoprotein Ras and is viewed as a potential target for cancer therapy. In this study, we synthesized a small library of dipeptidyl AOMKs to investigate the structural elements that contribute to the inhibitor properties of this class of molecules toward Rce1p and Ste24p. The compounds were evaluated using a fluorescence-based in vitro proteolysis assay. The most potent dipeptidyl AOMKs contained an arginine residue and the identity of the benzoate group strongly influenced potency. A 'warhead' free AOMK inhibited Rce1p and Ste24p. The data suggest that the dipeptidyl AOMKs are not mechanism-based inhibitors of Rce1p and Ste24p and corroborate the hypothesis that Rce1p is not a cysteine protease.
Copyright 2010 Elsevier Ltd. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Antineoplastic Agents / chemistry
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Antineoplastic Agents / pharmacology
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Cysteine Proteases / genetics
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Cysteine Proteases / metabolism*
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Dipeptides / chemistry
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Dipeptides / pharmacology*
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Drug Screening Assays, Antitumor
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Ketones / chemistry
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Ketones / pharmacology*
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Membrane Proteins / antagonists & inhibitors*
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Membrane Proteins / genetics
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Membrane Proteins / metabolism
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Metalloendopeptidases / antagonists & inhibitors*
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Metalloendopeptidases / genetics
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Metalloendopeptidases / metabolism
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Proprotein Convertases / antagonists & inhibitors*
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Proprotein Convertases / genetics
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Proprotein Convertases / metabolism
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Protease Inhibitors / chemistry
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Protease Inhibitors / pharmacology*
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Saccharomyces cerevisiae / enzymology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / antagonists & inhibitors*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism
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Substrate Specificity
Substances
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Antineoplastic Agents
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Dipeptides
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Ketones
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Membrane Proteins
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Protease Inhibitors
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Saccharomyces cerevisiae Proteins
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Cysteine Proteases
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Proprotein Convertases
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RCE1 protein, S cerevisiae
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Metalloendopeptidases
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STE24 protein, S cerevisiae