Figure 4
A: The k app vs. [I] plot for inhibition of the CEase-catalyzed hydrolysis of PNPB by (1R, αR)-1. [PNPB] = 50 μM. The solid line is a least-squares fit to Eq. (1) [17]; the parameters of the fit are K i = 0.27 ± 0.01 μM and k2 = (2.0 ± 0.2) × 10-3 s-1. B: % activity of CEase vs. the time period for inhibition of the enzyme with (1R, αR)-1 (50 nM) in the absence and presence of TFA (2 μM). [PNPB] = 50 μM. All the procedures followed those of Hosie et al. [17]. For the control experiments (squares), CEase was incubated alone at 25.0°C for a period of time before the inhibition reaction (CEase + PNPB + (1R, αR)-1). For the carbamate inhibition experiments (triangles), CEase was incubated with (1R, αR)-1 (50 nM) at 25.0°C for a period of time before the enzyme reaction (CEase + PNPB). For the protection experiments (circles), CEase was incubated with (1R, αR)-1 (50 nM) and TFA (2 μM) at 25.0°C for a period of time before the enzyme reaction (CEase + PNPB).