Inhibition of human caspases by peptide-based and macromolecular inhibitors.
Studies with peptide-based and macromolecular inhibitors of the caspase family of cysteine proteases have helped to define a central role for these enzymes in inflammation and mammalian apoptosis. A clear interpretation of these studies has been compromised by an incomplete understanding of the selectivity of these molecules. Here we describe the selectivity of several peptide-based inhibitors and the coxpox serpin CrmA against 10 human caspases. The peptide aldehydes that were examined (Ac-WEHD-CHO, Ac-DEVD-CHO, Ac-YVAD-CHO, t-butoxycarbonyl-IETD-CHO, and t-butoxycarbonyl-AEVD-CHO) included several that contain the optimal tetrapeptide recognition motif for various caspases. These aldehydes display a wide range of selectivities and potencies against these enzymes, with dissociation constants ranging from 75 pM to >10 microM. The halomethyl ketone benzyloxycarbonyl-VAD fluoromethyl ketone is a broad specificity irreversible caspase inhibitor, with second-order inactivation rates that range from 2.9 x 10(2) M-1 s-1 for caspase-2 to 2.8 x 10(5) M-1 s-1 for caspase-1. The results obtained with peptide-based inhibitors are in accord with those predicted from the substrate specificity studies described earlier. The cowpox serpin CrmA is a potent (Ki < 20 nM) and selective inhibitor of Group I caspases (caspase-1, -4, and -5) and most Group III caspases (caspase-8, -9, and -10), suggesting that this virus facilitates infection through inhibition of both apoptosis and the host inflammatory response.
Garcia-Calvo
M
M
Department of Enzymology, Merck Research Laboratories, Rahway, New Jersey 07065, USA. margarita_garcia-calvo@merck.com
Peterson
E P
EP
Leiting
B
B
Ruel
R
R
Nicholson
D W
DW
Thornberry
N A
NA
D000447:Aldehydes / Q000494:pharmacology*; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D006801:Humans; D010455:Peptides / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D015843:Serpins / Q000494:pharmacology; D013379:Substrate Specificity; D014764:Viral Proteins
D000447:Aldehydes; D000590:Amino Acid Chloromethyl Ketones; D015853:Cysteine Proteinase Inhibitors; D010455:Peptides; D011994:Recombinant Proteins; D015843:Serpins; D014764:Viral Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C074641:interleukin-1beta-converting enzyme inhibitor; D020169:Caspases