In vitro activity: Ac-DEVD-CHO is a potent inhibitor of caspase-3 (Ki = 230 pM). In contrast, caspase-2 cleaves the tetrapeptide substrate poorly and is only weakly inhibited by this aldehyde (Ki = 1.7 μM). Group III caspases are broadly inhibited by Ac-DEVD-CHO with Ki values ranging from 1 to 300 nM. Inhibition of caspase-3 by Ac-DEVD-CHO in isolated working-heart rat model significantly improves post-ischemic contractile recovery of stunned myocardium, even when given after the onset of ischemia. The mechanism(s) of protection by Ac-DEVD-CHO appear to be independent of apoptosis. Troponin I cleavage was not inhibited by Ac-DEVD-CHO.

Kinase Assay: Ac-DEVD-CHO is a potent inhibitor of caspase-3 (Ki = 230 pM). In contrast, caspase-2 cleaves the tetrapeptide substrate poorly and is only weakly inhibited by this aldehyde (Ki = 1.7 μM). Group III caspases are broadly inhibited by Ac-DEVD-CHO with Ki values ranging from 1 to 300 nM.

Cell Assay: Apaf-1–/– cells were treated with the indicated concentration of Ac-DEVD-CHO for 2 h prior to treatment with 4 μM CHX alone or with TNF for 6 h. LEHDase and DEVDase activities were standardized to the lactate dehydrogenase activity in the sample and are presented as percentages of the activity in TNF-plus-CHX-treated cells not treated with Ac-DEVD-CHO (0 μM).