Table 1.
Kinetic parameters of disulfiram inhibition of two coronaviral PLpros.
| PLpro/inhibitor | KM (μM) | kcat (s−1) | Kis (μM) | Kinact (μM)c | kmax (10−2s−1)d |
|---|---|---|---|---|---|
| SARS-CoV PLpro | |||||
| No inhibitor | 19.5 ± 4.9a | 0.18 ± 0.03a | |||
| Disulfiram | 5.4 ± 0.3 | 1.1 ± 0.03 | |||
| Competitive | 18.3 ± 2.3b | 0.17 ± 0.01b | 4.6 ± 0.4b | ||
| Mixed inhibition | 19.5 ± 2.5b | 0.18 ± 0.01b | 6.0 ± 1.1b | ||
| 43.8 ± 5.6c | |||||
| C271 mutant | |||||
| No inhibitor |
24.6 ± 3.1a |
0.12 ± 0.01a |
|||
| MERS-CoV PLpro | |||||
| No inhibitor | 28.8 ± 4.6a | 0.01 ± 0.0004a | |||
| Disulfiram | 30.5 ± 1.8b | 0.01 ± 0.0003b | 20.1 ± 0.7b | ||
a
The steady-state kinetic parameters of the PLpros were determined according to the Michaelis-Menten equation.
b
In the presence of disulfiram, the best-fitted kinetic parameters and Kis were determined in accordance with competitive (Eq. (3)) or mixed inhibition (Eq. (4)) and noncompetitive (Eq. (2)) inhibition models for SARS-CoV and MERS-CoV PLpro, respectively.
c
The value is αKis, the inhibition constant for the enzyme-substrate-inhibitor complex.
d
Kinact and kmax values are from the best fit to the saturation equation (Eq. (7)).