Table 4. Kinetic Characterization of the Inhibition of Cathepsins B, S, L, and K by Dipeptide Alkynes with 3-Methylphenylalanine or 3-Iodophenylalaninea.
|
kinact/KI (M–1 s–1) |
||||||
|---|---|---|---|---|---|---|
| compound | R1 | R2 | CatB | CatS | CatL | CatK |
| 2b | 4-fluorobenzoyl | Me | 85(3) | 682(85) | 281(30) | 48(5) |
| 2k | I | 1179(222) | 10133(842) | 2128(230) | 121(5) | |
| 2c | diphenylacetyl | Me | 771(17) | 47(11) | 381(43) | n.i. |
| 2l | I | 301(25) | 859(83) | 552(58) | 76(5) | |
| 2f | 3-iodobenzoyl | Me | 45(1) | n.i. | 1968(153) | n.i. |
| 2m | I | 225(24) | 4368(235) | 2876(252) | n.i. | |
a
The measurement was performed in three independent experiments (each as a duplicate determination) in assay buffer (pH 6.0) containing 1.5% DMSO. n.i. = no inhibition; i.e., no evidence of irreversible inhibition was discernible within the considered time and concentration ranges. Data shown are mean values ± SEM of three experiments, each performed in duplicate.