Figure 4.
Kinetics of E. coli t6A formation in the full reaction and isolated second step with purified TC-AMP as substrate. (A) Full reaction mixture with L-threonine as variable substrate fit to MM kinetics (Equation 1). (B) Full reaction mixture with ATP as variable substrate ≤1 mM. (C) Full reaction with ATP as variable substrate showing substrate inhibition at high concentrations (fit to Equation 3) (D) Full reaction with tRNALysUUU as the variable substrate fit to Morrison Equation (2). (E) Isolated second step of reaction with TC-AMP as variable substrate and 1 mM ATP fit to Morrison equation (Equation 2). (F) Second step of the reaction with TC-AMP (10 μM) as substrate and variable ATP displaying substrate inhibition as in (C). (G) Second step of the reaction with constant TCAMP (10 μM) and ATP as the variable substrate (≤1 mM) fit to MM Equation (1).