Research / 2019 / Article / Tab 2

Research Article

Crystal Structure of 4-Hydroxyphenylpyruvate Dioxygenase in Complex with Substrate Reveals a New Starting Point for Herbicide Discovery

Table 2

Comparison of apparent kinetic parameters for reaction of the WT and mutants of AtHPPD at pH 7.0. Each experiment was carried out in triplicate.

Enzyme (s−1) (μM)/

WT1.079 ± 0.0531.87 ± 0.370.5770 ± 0.1142
N423A0.545 ± 0.06115.66 ± 4.290.0348 ± 0.0095
F381A0.924 ± 0.0329.10 ± 0.940.1015 ± 0.0105
Q293A0.014 ± 0.00190.41 ± 11.330.00015 ± 0.00001
Q307A0.176 ± 0.00430.31 ± 1.670.0058 ± 0.0003
S267A0.249 ± 0.0255.33 ± 1.590.0467 ± 0.0139
N282A0.039 ± 0.00310.83 ± 2.330.0036 ± 0.0008

Reactions were conducted in air-saturated 20 mM HEPES (pH 7.0) at 25°C and kinetically analyzed as described in Experimental Procedures. Errors for individual parameters were obtained from the nonlinear regression fit of the data to the Michaelis-Menten equation.