Fig. 5. .

Concentration responses of arylsulfonamide Redox Cycling Compounds (RCCs) in 0.8 mM reducing reagents. In triplicate wells 20 μL of 4 of the arylsulfonamide RCCs at the indicated concentrations, ranging between 0.2 and 50 μM, were mixed together with 20 μL of the indicated reducing reagents at 0.8 mM: DTT (•), TCEP (), GSH (), or HBSS () (no reducing agent). The final concentrations of the components in the 60 μL assay volume are indicated. After 15 min, 20 μL of phenol red-HRP detection reagent was added and the assay was incubated for 5 min at ambient temperature before termination by the addition of 10 μL of 1 N NaOH and measurement of the absorbance at 610 nm in the M5 Spectromax plate reader. The data are presented as the mean absorbance ± SD of the mean of the triplicate wells, and the data were fit to a sigmoidal dose–response variable slope equation Y = bottom + [top-bottom]/[1 + 10ˆ(LogEC₅₀-X)*HillSlope] by the Graphpad Prism software 4.03. (A) SID 24814503, (B) SID 22405508, and (C) SID 17511877.