Fig. 2.

Inhibition of MERS-CoV PL^pro by 6MP (A), 6TG (B), or mycophenolic acid (C). The proteolytic activity of PL^pro was measured in the presence of different peptide substrate concentration (4–50 μM) and various inhibitor concentrations (0–50 μM for 6MP or 6TG and 0–500 μM for mycophenolic acid). The solid lines in panel A and B are the best fit by the competitive inhibition (Eq. (1)) and those in panel C are the best-fit by the noncompetitive inhibition (Eq. (2)). The R_sqr are 0.978, 0.979, and 0.988, respectively. All assays were repeated several times to ensure reproducibility. The kinetic parameters such as K_m, k_cat and K_is from the best fit were shown in Table 2.