Figure 5. Determination of IC50 values for wild-type and mutant PEPC from F. pringlei (C3) and F. trinervia (C4).

(a) The mean activity values of F. pringlei wild-type C3 PEPC (open circles) and F. pringlei R884G mutant (solid circles) are plotted against the concentration of the feedback inhibitor malate. The calculated IC₅₀ values are 2.9 mM for the wild-type (solid curve) and 8.7 mM for the R884G mutant C3 PEPC (dashed curve). (b) Plot of mean activity values of F. trinervia wild-type C4 PEPC (open circles) and F. trinervia G884R mutant (closed circles). IC₅₀ values calculated from the experimental data are 8.4 mM for wild-type and 2.8 mM for the mutant C4 PEPC. S.d. was calculated from three independent experiments. Activities were measured in triplicates for each experiment.