<p>Initial velocities were determined at 23°C to limit the reaction to a single kinetic phase as much as possible. <b>A.</b> Titration of NADH at [BQ] = 10 µM (open squares), 20 µM (triangles), 50 µM (circles), 100 µM (filled squares). <b>B.</b> Titration of BQ at [NADH] = 10 µM (open squares), 20 µM (triangles), 50 µM(circles), 100 µM(filled squares). Solid lines represent non-linear least-squares best fit of the Michaelis-Menten equation to the data points. The values of apparent Km and apparent Vmax returned from the fit are given in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0043902#pone-0043902-t001" target="_blank">Table 1</a>.</p
