Figure 1.

Reactivity of peptide-FMK reagents. (A) BD-FMK and ZVAD-FMK do not inactivate Granzyme B. Detergent extracts of cloned murine CTL were used as a source of enzyme with the thiobenzyl ester BAAD-S-Bzl as substrate. The indicated final concentrations of inhibitors were preincubated with enzyme for 2 h at 37°C before addition of substrate. ZAAD-CMK was tested as a positive control. (B) P1-Asp FMKs inactivate apoptotic DEVDase from Jurkat. A detergent extract of antiFas–treated Jurkat cells was used as a source of active CPP-32 or similar ICE family protease with a fluorometric assay of ZDEVD-AFC hydrolysis. The indicated concentrations of peptide-FMK reagents were preinbucated with the extract at 0°C for 15 min before addition of substrate to begin the assay. (C  ) Peptide-FMK inhibition of stimulated human monocyte IL-1β processing. An SDS gel of secreted and immunopreciptated ³⁵S-labeled IL-1β is shown. The control lane C received no S. aureus. The nonspecific band at 22 kD was not seen in all experiments.