Effects of mutation of A441 on the steady-state kinetic parameters of So BADH. Wild-type and mutant SoBADH enzymes were assayed at pH 8.0 and 30°C with BAL as variable substrate at fixed 0.2 mM NAD+. Other conditions are given in the Methods section. The kinetic parameter values were calculated from the best fit of initial velocity data to the Michaelis-Menten equation by non-linear regression. Each saturation curve was determined at least in duplicate using enzymes from two different purification batches. Bars indicate standard deviations. In the inset the kcat/Km values of A441V, A441F and A441I are plotted using a scale smaller than that of the main figure.