Figure 9.

Estimated fractional uncertainty for k_on measurements at the (A) lower and (B) upper end of accessibility. A) Summary data of five experiments collected for TT – RR binding at 5 °C, 100 mM KCl, where the average forward rate constant is 600 M⁻¹s⁻¹. In each experiment the starting cell concentration was 10 µM, so k_on·[M]_init = 0.006 s⁻¹. B) Summary of data collected for the SET7/9 lysine methyltransferase, for which the average forward rate constant is 22,000 M⁻¹s⁻¹, and the average starting cell concentration was 6.4 µM (average k_on·[M]_init = 0.14 s⁻¹). Each symbol reflects the estimated contribution of each source of uncertainty to a single injection at that point in a titration. Averaging of all data points in a titration reduces the uncertainty from uncorrelated sources of error as discussed in Section 4.2.3.