TABLE 1.
Self-masked aldehyde inhibitors of cysteine proteases and their effects on SARS-CoV-2 infected cells a .
|
Ki* (nM) | Anti-CoV-2 EC50 (µM) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Compound | R4 | R3 | R2 | R1-A | hCatL | Cruzain b | hCatB | 3CLpro b | Vero E6 Cells | A549/ACE2 Cells |
| 1 | H |
|
Bz |
|
0.14 ± 0.01 | 0.44 ± 0.02 | ND | >10,000 | 0.47/7.5 | >20 |
| 2 | H | Cbz | Bz |
|
12.6 ± 0.4 | 49 ± 2 | 4,500 ± 100 | >10,000 | 10 ± 5 | >20 |
| 3 | OMe | Cbz | Bz | o-Tyr-CHO | 17 ± 0.9 | 350 ± 30 | 5,500 ± 400 | >10,000 | ND | ND |
| 4 | Me | Cbz | Bz | o-Tyr-CHO | 26 ± 0.9 | 103 ± 5 | 6,100 ± 900 | >10,000 | ND | ND |
| 5 | CI | Cbz | Bz | o-Tyr-CHO | 12.1 ± 0.3 | 70 ± 10 | 1400 ± 100 | >10,000 | ND | ND |
| 6 | F | Cbz | Bz | o-Tyr-CHO | 10.3 ± 0.5 | 48 ± 2 | 2,300 ± 200 | >10,000 | 4 | ND |
| 7 | CO2Me | Cbz | Bz | o-Tyr-CHO | 4.8 ± 0.2 | 18.0 ± 0.5 | 670 ± 30 | >10,000 | 2.5 | ND |
| 8 | H |
|
Bz | o-Tyr-CHO | 9.0 ± 0.4 | 47 ± 2 | 1270 ± 70 | >10,000 | 9 ± 2 | ND |
| 9 | H |
|
|
|
22 ± 4 | ND | ND | 9 ± 2 b | ND | 3.75 |
| 10 | H | Me-Pip | Bz |
|
NA | NA | NA | NA | 2.5 | 0.31 |
| 11 | H | Me-Pip | Bz |
|
NA | NA | NA | NA | 2.5 | 0.62 |
| 12 | H | Me-Pip | Bz |
|
NA | NA | NA | NA | 4 | 0.31 |
| K777c | NA | Me-Pip |
|
|
kinact/KI = 3 ± 1 µM−1-s−1 | kinact/KI = 1.0 ± 0.3 µM−1-s−1 | kinact/KI = 0.009 ± 0.004 µM−1-s−1 | >10,000 | 0.62 c /0.15 | <0.078 c |
| PF-07321332 |
|
>100mM d | ND | >100mM d | 3.11 d | 0.074 d />20 | 0.077 d /0.47 | |||
a
Inhibition constants (Ki* values) obtained after 30-min incubation of inhibitors with cysteine proteases as described in Methods.
b
Data for human cathepsins B and L were obtained at pH 5.5, and at neutral pH for cruzain (pH 7.5) (Zhai and Meek, 2018) and for 3CL protease (pH 7.2).
c
Kinetic parameters of inactivation for K777 are as reported in Mellott et al. (2021).
d
Data from Owen et al. (2021); NA, not applicable; ND, no data.