Figure 4.

Determination of true catalytic rates for recombinant N1 and N2.A, graph displaying the reactivity of recombinant N1, N2, NanA, NanB, and NanC with the influenza neuraminidase titration reagent TR1. B, correlation plot showing the number of F₂Mu molecules that were produced following incubation of TR1 with increasing numbers of N1 and N2 molecules. The slope of the linear fit corresponds to the fraction of active N1 and N2 molecules in each recombinant preparation. C, the theoretical N1 and N2 k_cats at each pH (Fig. 3C, upper panel) were adjusted for the fraction of enzymatically active molecules to determine the true k_cat values. NanA, NanB, and NanC, theoretical k_cats (Fig. 3D, upper panel) were included for reference. TR1, titration reagent 1.