Fig. 3: Characterization of myricetin binding with the SARS-CoV-2 3CLpro and half-life determination of myricetin reacting with GSH.
a Mass spectrometry analysis for the SARS-CoV-2 3CLpro treated with DMSO or myricetin. Three independent experiments were performed. b Proposed reaction adduct of the SARS-CoV-2 3CLpro with myricetin. c The SARS-CoV-2 3CLpro (at a final concentration of 100 nM) was incubated with five different concentrations of myricetin (2.5, 5, 10, 20, and 40 µM), respectively. For each concentration, the protease activity at different time was measured by the FRET-based protease assay and plotted against the incubation time to obtain the kobs value (an absolute value of the slope of each linear curve). d The resulting kobs values were plotted versus inhibitor concentrations to generate the kinact and Ki values of myricetin binding with the SARS-CoV-2 3CLpro. e Myricetin (at a final concentration of 400 µM) was incubated with 10 mM GSH for 0, 120, 240, 360, 480, and 600 min, in the presence or absence of oxygen, respectively. The remaining myricetin was determined by LC-MS. f Ln (the percentage of the remaining myricetin) was plotted against incubation time to generate the half-life time of myricetin reacting with GSH. Error bars represent mean ± SD of three independent experiments in Fig. c–f.
