Figure 3.
(a) Concentration response of the known 3CLpro inhibitor, GC376. An IC50 of 0. 17 μM was determined for the inhibition of SARS-CoV-2 3CLpro. The substrate concentration was 20 μM and enzyme concentration was 50 nM in this experiment. (b) Scatter plot of the results from a DMSO plate in the 3CLpro enzymatic assay in a 1536-well plate, where columns 1 and 2 in the plate contain substrate only, column 3 includes GC376 titration (1:3 dilution series from 57.5 μM), and columns 5–48 contain DMSO (23 nL DMSO in 4 μL reaction solution).