Table 3. Kinetic parameters of six internally quenched substrates (ACC-GDEV(D/E)-XKK(DNP)G-NH2) measured for caspase-3 and caspase-7.
Substrate | Caspase-3 |
Caspase-7 |
||||||
---|---|---|---|---|---|---|---|---|
kcat, s−1 | KM, μM | kcat/KM, M−1s−1 | kcat/KM, E/D ratio | kcat, s−1 | KM, μM | kcat/KM, M−1s−1 | kcat/KM, E/D ratio | |
DEVD/G | 5.16 | 3.17 | 1629000 | — | 0.926 | 4.80 | 193600 | — |
DEVD/A | 4.69 | 4.21 | 1930500 | — | 1.04 | 6.29 | 193590 | — |
DEVD/S | 6.52 | 4.40 | 1489800 | — | 0.795 | 6.38 | 124700 | — |
DEVE/G | 0.665 | 3.77 | 176700 | 0.11 | 0.475 | 7.32 | 65100 | 0.34 |
DEVE/A | 0.357 | 15.98 | 22360 | 0.012 | 0.0162 | 16.52 | 958 | 0.005 |
DEVE/S | 0.0646 | 7.30 | 8950 | 0.006 | 0.0032 | 10.36 | 307 | 0.0025 |
The enzyme concentrations varied from 1 to 100 nM depending on the substrate, as described in the Methods section.