Fig. 2. Potency determinations using an E. coli GUS enzyme assay.

Concentration response data for compounds was normalized to controls with and without enzyme and plotted as percent activity. Potency determinations of nialamide (●), isocarboxazid (▲), phenelzine (□), amoxapine (■), loxapine (○) and mefloquine (♦) resulted in average IC₅₀ values (nM) and SDs of 71 ± 32, 128 ± 56, 2,282 ± 1,041, 388 ± 98, >100,000 and 1,212 ± 234, respectively. The average Hill slope values derived from the IC₅₀ curves of all active drugs ranged from 0.93 – 1.26. Data points represent the average of three determinations per concentration and error bars represent standard deviation. Data are representative of three independent experiments.