Fig. 4
From: Catalytic mechanism and molecular engineering of quinolone biosynthesis in dioxygenase AsqJ
Activity measurements of wt and engineered AsqJ. Turnover of the wt and V72I-mutated AsqJ for the non-methylated substrate analog (1d) from reverse-phase HPLC/MS-coupled activity assays in the presence of FeII, αKG, oxygen, and ascorbic acid. The absorbance at λ = 280 nm is shown for 1d and the desaturated reaction intermediate 2d (see Supplementary Fig. 13 for further characterization). The reaction progress was analyzed after 20 s (black trace), 1 min (dark blue), 2 min (light blue), 5 min (dark green), 10 min (light green), and 30 min (orange), showing that 2d forms already after 20 s in V72I
