Figure 1.

Measurement of kinetic parameters for translation termination by RF1 at the near-cognate codon UAC in the presence or absence of RF3: an example of an RF accuracy experiment. The rate v for peptide release was measured as described in the text at different concentrations of RF. The rate v was estimated from the relation v = −ln(1 − R/R_O)/T, where R/R_O is the fraction of released oligopeptide during the incubation time T, and depends on the concentration [RF] of RF1 or RF2 as in a normal Michaelis–Menten equation: v = [RF]⋅k_cat/(K_M + [RF]). The y-intercept(s) gives the k_cat, the x-intercept(s) gives the k_cat/K_M, and the slope is equal to −K_M.