Production of active SARS-CoV-2 main protease (Mpro) in E. coli
(A) Bacterial expression and purification of Mpro. The SDS-PAGE gel was stained with coomassie brilliant blue R250. M: Protein ladder; 1: Total cell extract; 2–4: Pure Mpro (34 kDa).
(B) Measurement of the initial velocity of Mpro enzyme reaction. All initial rates were obtained by fitting the linear portion of the curves to a straight line.
(C) Determination of the Km value. The Michaelis-Menten equation was plotted using GraphPad Prism 8.0 according to the initial rates, and the Km and Vmax values were recorded as 19.28 μM and 139.5 ΔRFU/s, respectively. This assay was performed in triplicate.