FIG 5.

Determination of the mechanism of action of the hit compounds relative to ATP and phenylalanine. IC₅₀s were determined by using aminoacylation assays. The final compound concentrations in the IC₅₀ reactions ranged from 0.4 to 200 μM. In assays to determine competition with ATP, the phenylalanine concentration was fixed at 100 μM. IC₅₀s were determined for BM03E08 (A), BM04E04 (B), and BM07F03 (C) at six different ATP concentrations (25, 50, 100, 250, 500, and 1000 μM). In assays to determine competition with phenylalanine the ATP concentration was fixed at 2.5 mM. IC₅₀s were determined for BM03E08 (D), BM04E04 (E), and BM07F03 (F) at five different Phe concentrations (25, 50, 100, 200, and 300 μM).