Comparison of kinetic parameters and binding affinity of WT-DKR and nine mutantsa,b.

aInitial velocity was obtained under conditions with varying 2-chloro-1-phenylethanone concentrations (0.1–3.4 mM) and a constant and saturating NADH concentration (0.15 mM). Data are the average of two measurements.bDissociation constants were determined using 80 µg protein as described in the Methods; Kd values were calculated by fitting the data to the quadratic equation. Kd values are the average of three measurements.cAmino acids at residue 222.dThe kcat values were calculated based on the Michaelis-Menten model.