K_m values of AtAPY1-GFP for GDP, UDP and IDP.

<p>Michaelis-Menten plots of the initial reaction velocities (v) for different concentrations of substrate are shown. Different amounts of AtAPY1-GFP enzyme were used in (A), (B) and (C) as a result of different starting material. The enzyme velocities were determined by the continuous assay. For each substrate concentration, the mean velocity calculated from two parallel reactions was plotted. The initial velocities were linear over time for ≥ 30 min. Each initial velocity was determined from a minimum of 24 data points from this linear phase. The error bars represent the standard deviations of the velocity means. The data set is representative of six (A, B) and three experiments (C), respectively.