Ki determination of compound 1 and mode of inhibition with regard to UTP substrate. Reaction velocities were measured at different UTP concentrations (0.25, 0.50, 1.0, 2.5, 5.0, 10, 25 and 50 µM, plotted as open diamonds, closed diamonds, open circles, closed circles, open squares, closed squares, open triangles and closed triangles, respectively) with the template/primer fixed at 0.25 µM. Dixon and Cornish-Bowden plots of the reciprocal velocity with compound 1 at concentrations of 0, 2.5, 5, 10, 20 and 40 µM. Both plots display intersects on the x-axis and reflect non-competitive inhibition with regard to UTP (Ki competitive = Ki uncompetitive = 20 µM).