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. Author manuscript; available in PMC: 2016 Oct 1.
Published in final edited form as: J Biomol Screen. 2015 Jun 26;20(9):1160–1170. doi: 10.1177/1087057115591120

Figure 5.

Figure 5

Determination of the mode of action of BT_03F04 and BT_04B09 relative to ATP and Glu. IC50s were determined using the aminoacylation assay. Final compound concentrations in the IC50 reactions ranged from 200 to 0.4 µM. The glutamic acid concentration was fixed at 100 µM, and IC50s were determined at six different ATP concentrations ranging from 25 to 1000 µM in assays to determine competition with ATP. The ATP concentration was fixed at 2 mM, and IC50s were determined at five different amino acid (Glu) concentrations ranging from 25 to 300 µM to determine competition with the amino acid. The data were fit to the sigmoidal dose–response model using XLfit (IDBS). A lack of change of IC50 values when the substrate is increased is indicative of noncompetitive inhibition. An increase in IC50 values as substrate is increased is indicative of competitive inhibition. Reactions containing BT_03F04 were carried out in increasing concentrations of (A) ATP and (B) glutamic acid. Reactions containing BT_04B09 were carried out in increasing concentrations of (C) ATP and (D) glutamic acid.