Table 1.

Kinetic parameters of Mpro and its mutants

Protein	Km (μM)∗	kcat (s−1)∗	kcat/Km (s−1 M−1)	kcat (s−1) by nonlinear fitting†
Wild-type	222.6 ± 19.0	0.63 ± 0.02	2830 ± 303	1.4 ± 0.2
E166A	353.4 ± 48.0	0.31 ± 0.01	877 ± 132	ND‡
	K′ (104μM)	kcat (s−1)	h
R298A	3.9 ± 2.3	0.10 ± 0.004	2.0 ± 0.1	0.7 ± 0.4
R298L	9.5 ± 6.2	0.48 ± 0.06	1.8 ± 0.1	2.3 ± 0.9

^∗Data of wild-type Mpro and E166A mutant were fitted to the Michaelis-Menten equation (Eq. 1) and the R_sqr values were 0.994 and 0.987, respectively. Those of mutants were fitted to the Hill equation (Eq. 2), and the R_sqr values were 0.998 and 0.996, respectively. All the assays were repeated several times to ensure reproducibility.

^†Catalytic constant was calculated by the nonlinear dependence equation (Eq. 3). The best-fitting R_sqr values for wild-type, R298A, and R298L were 0.995, 0.99 and 0.993, respectively.

^‡Not determined.