Figure 4

Eadie-Hofstee plots for determining substrate binding affinities. Reaction velocity (v_o) in micromoles•min^-1 is normalized to total ribozyme concentration (1 nM). Indicated on each plot are the ribozyme species, the concentration of MgCl₂ in millimolar (in parentheses) and the calculated Km value (negative of the slope). Gray trendlines for RzC at 0.5 mM MgCl₂ subdivide the data set into regions of steep and shallow slopes with Km values of 90 nM and 12 nM.