Table 2.
Inhibition of the proteasome by GLA and its derivatives.
| Compounds | R1 | R2 | IC50 (µM) (ChT-L)a | IC50 (µM) (T-L)a | IC50 (µM) (Ca-L)a |
|---|---|---|---|---|---|
| 1 | H | OH | 22.3 | >40 | >40 |
| 2b |  |
OH | 0.87 | - | - |
| 3 |  |
OH | 8.70 | - | - |
| 4 |  |
OH | 2.63 | - | - |
| 5 |  |
OH | 6.86 | - | - |
| 6 |  |
OH | 1.39 | - | - |
| 7 |  |
OH | 1.93 | - | - |
| 8 |  |
OH | 0.29 | 3.32 | 5.02 |
| 9b |  |
OH | >40 | - | - |
| 10 |  |
OH | >40 | - | - |
| 11 |  |
OH | 1.92 | - | - |
| 12 |  |
OH | 0.35 | 19.3 | 26.5 |
| 13 |  |
OH | 2.08 | - | - |
| 14 |  |
OH | 2.27 | - | - |
| 15 |  |
OH | 1.05 | - | - |
| 16 |  |
OH | 1.78 | - | - |
| 17 |  |
OH | 0.22 | 2.91 | 3.56 |
| 18 |  |
OH | 0.31 | - | - |
| 19b | H |  |
>40 | - | - |
| 20b |  |
 |
>40 | - | - |
| 21b |  |
 |
3.09 | - | - |
| LLM-Fc | 5.25 | >25 | 22.5 | ||
| Lactacystinc | 5.6 | >30 | >30 |
a
The inhibition of chymotrypsin-like (ChT-L), trypsin-like (T-L), and caspase-like (Ca-L) activities of the 20S proteasome was determined in the presence of various concentrations of the compounds as previously described (13). The value of IC50 was averaged from three independent assays.
b
These compounds were previously reported for their anti-HIV activities.
c
LLM-F and lactacystin are known proteasome inhibitors.