Inhibition of the PRODH activity of PutA86–630 by 1, 2, 3, 4, 16, 17, and 18. The assays were performed at room temperature with 0–500 mM L-proline, 4 mM o-AB, 0.15 mM menadione, and 63 nM PutA86–630 in a buffer containing 20 mM MOPS pH 7.5 and 10 mM MgCl2. The data for each inhibitor were analyzed by global fitting to the competitive inhibition model using Origin software. Kinetic constants are listed in Table 1.