FIGURE 2. Kinetic characterization of designed catalysts.

a, Catalytic activity was measured by monitoring the product formation over time for KE59 (open circles) and KE70 (filled circles) at 400 M substrate concentration. The y axis is the product concentration divided by the catalyst concentration that corresponds to the number of substrate turnovers. Deleting the catalytic base in both designs largely eliminates catalytic activity (open and filled triangles). Mutating Asp 44 of the catalytic dyad of KE70 to Asn (filled squares) causes a 2.5-fold reduction in activity. b, Michaelis–Menten plots for a representative selection of designed catalysts. The reaction velocity v divided by catalyst concentration is plotted on the y axis and the substrate concentration on the x axis. Some designs (for example, KE10 (open squares) and KE61 (open triangles)) show no saturation up to the maximal substrate solubility.