FIGURE 4.

Reduction of ricin in an oxidizing environment. To check the ability of TMX to reduce ricin in different redox conditions we included in the buffer (0.1 m phosphate buffer) different GSSG:GSH ratios. To set up the oxidizing environment the samples were incubated with 750 μm GSSG and 250 μm GSH (lanes 1 and 3). To set up the reducing environment the samples were incubated with 250 μm GSSG and 750 μm GSH (lanes 2 and 4). The toxin was added to samples containing oxidized TMX (lanes 1 and 2) or DTT-prereduced TMX (lanes 3 and 4). After a 60-min incubation at 37 °C, the samples were analyzed for the yield of reduced ricin by Western blotting.