Fig. 5.

Light-exposed MP Biomedicals and RR535 inhibit DUSP5 PD(WT) in a time-dependent manner while inhibition by RR601 is not time-dependent. DUSP5 PD(WT) initial velocity monitored utilizing pNPP as the substrate versus increasing concentrations of (a) MP Biomedicals, (b) RR535 (0.1 to 300 μM) prepared from compounds exposed to room light for 90 days, and (c) freshly prepared RR601 (0.1 to 300 μM). IC₅₀ ± SE values were determined from rate data collected during the first ten minutes, between 15 and 25 min and again between 30 and 40 min during the reaction period (Table 1). Data points represent the mean ± SD of three trials with eight wells at each compound concentration