Table 2. Binding Data (pKi Values) of Pentapeptides 1–38 at Casp2 and Casp3a,b.
| pKi ± SD |
||||||
|---|---|---|---|---|---|---|
| sequence | Comp. | Casp2 | N | Casp3 | N | Ki(Casp3)/Ki(Casp2) |
| AcYKPVD-CHO | 1 | 4.56 ± 0.43c | 3 | 4.73 ± 0.10 | 4 | 0.68 |
| AcVDVAD-CHO | 2 | 7.85 ± 0.08c | 5 | 7.73 ± 0.09 | 5 | 1.33 |
| AcVDPVD-CHO | 3 | 4.82 ± 0.12c | 2 | 5.70 ± 0.04 | 2 | 0.13 |
| AcVDKVD-CHO | 4 | 7.40 ± 0.02c | 5 | 7.28 ± 0.09 | 4 | 1.32 |
| AcVDVKD-CHO | 5 | 7.63 ± 0.05c | 4 | 6.91 ± 0.07 | 4 | 5.16 |
| AcVDVVD-CHO | 6 | 7.77 ± 0.12c | 4 | 7.81 ± 0.13 | 4 | 0.91 |
| AcVDKAD-CHO | 7 | 7.35c | 1 | 7.22 ± 0.22 | 3 | 1.35 |
| 7.09 ± 0.11d | 2 | 0.73 | ||||
| AcYKKVD-CHO | 8 | <4c | 2 | <4.5 | 2 | |
| AcYKVKD-CHO | 9 | <4c | 1 | <4 | 2 | |
| <4d | 1 | |||||
| AcVKVVD-CHO | 10 | <4d | 2 | 5.16 ± 0.06 | 2 | <0.07 |
| AcVKKVD-CHO | 11 | <4c | 1 | 4.78 ± 0.02 | 2 | <0.17 |
| <4d | 1 | |||||
| AcVKVKD-CHO | 12 | <4c | 2 | <4 | 2 | |
| AcVKPVD-CHO | 13 | <4c | 2 | 4.88 ± 0.04 | 2 | <0.16 |
| AcYKVVD-CHO | 14 | <4d | 2 | 5.31 ± 0.07 | 2 | <0.05 |
| AcYDKVD-CHO | 15 | 7.39 ± 0.01c | 2 | 7.75 ± 0.13 | 3 | 0.44 |
| 7.18d | 1 | 0.27 | ||||
| AcYDVKD-CHO | 16 | 7.83 ± 0.04c | 4 | 7.13 ± 0.02 | 4 | 5.06 |
| AcYDPVD-CHO | 17 | <4c | 1 | 5.61 ± 0.04 | 2 | <0.02 |
| <4d | 1 | |||||
| AcVD(Orn)VD-CHO | 18 | 7.37 ± 0.05c | 2 | 7.52 ± 0.07 | 3 | 0.70 |
| 6.92d | 1 | 0.25 | ||||
| AcVD(Dab)VD-CHO | 19 | 7.44 ± 0.08c | 4 | 7.54 ± 0.02 | 4 | 0.78 |
| AcVD(Dap)VD-CHO | 20 | 6.53 ± 0.07c | 2 | 7.38 ± 0.15 | 3 | 0.14 |
| 6.18d | 1 | 0.06 | ||||
| AcVDRVD-CHO | 21 | 7.38 ± 0.13c | 3 | 7.21 ± 0.08 | 3 | 1.48 |
| AcVD(AcK)VD-CHO | 22 | 7.70 ± 0.02c | 2 | 7.96 ± 0.22 | 3 | 0.56 |
| 7.41d | 1 | 0.29 | ||||
| AcVDV(Orn)D-CHO | 23 | 7.45 ± 0.07c | 4 | 6.60 ± 0.08 | 4 | 7.07 |
| AcVDV(Dab)D-CHO | 24 | 7.26 ± 0.07c | 4 | 5.82 ± 0.18 | 4 | 27.7 |
| AcVDV(Dap)D-CHO | 25 | 6.77 ± 0.17c | 4 | 6.14 ± 0.09 | 4 | 4.30 |
| AcVDVRD-CHO | 26 | 7.37 ± 0.04c | 2 | 7.12 ± 0.30 | 3 | 1.81 |
| 7.07d | 1 | 0.91 | ||||
| AcVDV(AcK)D-CHO | 27 | 7.53 ± 0.18c | 2 | 7.60 ± 0.20 | 3 | 0.85 |
| 7.30d | 1 | 0.49 | ||||
| AcTDKTD-CHO | 28 | 6.84 ± 0.17c | 2 | 7.03 ± 0.06 | 3 | 0.63 |
| 6.53d | 1 | 0.31 | ||||
| AcVDKID-CHO | 29 | 7.57 ± 0.04c | 2 | 7.57 ± 0.19 | 3 | 1.00 |
| 7.16d | 1 | 0.39 | ||||
| AcVDKFD-CHO | 30 | 7.24 ± 0.06c | 2 | 7.34 ± 0.08 | 3 | 0.79 |
| 6.78d | 1 | 0.27 | ||||
| AcVDFVD-CHO | 31 | 7.00 ± 0.17c | 2 | 8.02 ± 0.26 | 3 | 0.10 |
| 6.50d | 1 | 0.03 | ||||
| AcVDKPD-CHO | 32 | 7.66 ± 0.03c | 2 | 7.70 ± 0.25 | 3 | 0.91 |
| 7.38d | 1 | 0.48 | ||||
| AcVDPPD-CHO | 33 | <4c | 2 | <4.5 | 2 | |
| AcVDPKD-CHO | 34 | <4c | 1 | <4 | 2 | |
| <4d | 1 | |||||
| AcIDVKD-CHO | 35 | 7.68 ± 0.04c | 4 | 6.80 ± 0.10 | 4 | 7.53 |
| AcYDVVD-CHO | 36 | 7.50 ± 0.03d | 3 | 8.43 ± 0.07 | 3 | 0.12 |
| AcLDESD-CHO | 37 | 6.85 ± 0.03c | 3 | 7.40 ± 0.02 | 3 | 0.28 |
| AcDEVD-CHO | 38 | 6.60 ± 0.32c | 3 | 8.68 ± 0.26 | 3 | 0.008 |
a
Selectivity expressed as Ki(Casp3)/Ki(Casp2).
b
Data shown are mean values ± SD of N independent experiments, each performed in duplicate or triplicate. Data were analyzed by nonlinear regression and were best fitted to sigmoidal concentration–response curves.
c
Data represent pKi values determined with Casp2.
d
Data represent pKi values determined with cpCasp2.