TABLE 2.
Hemi-labeling of caspase-1 dimer leads to enzyme activation
Kinetic constants for hybrid-tagged caspase-1 either with or without a single z-VAD-fmk on the His-tagged p20 subunit (see Fig. 4) are shown. The simple Michaelis-Menten fit here does not take into account the monomer-dimer equilibrium and thus yields a higher effective Km(eff) than in our more detailed model in Fig. 4, which provides the Km of the dimeric hemi-labeled enzyme. Standard errors are within 10% of reported values based on data collected in triplicate.
| Construct | Km(eff) | kcat | kcat/Km | Ratio |
|---|---|---|---|---|
| μm | s−1 | m−1·s−1 | kcat/Km | |
| Unlabeled caspase-1 control | 1.9 | 0.11 | 5.6 × 104 | 1 |
| Hemi-labeled caspase-1 | 3.8 | 1.93 | 5.1 × 105 | 9.1 |