Figure 2.

Effect of photochemical treatment on gelonin-induced inhibition of protein synthesis. For the ‘light before’ strategy the cells were first incubated with 20 μg ml⁻¹ AlPcS_2a for 18 h, then for another 4 h in AlPcS_2a-free medium before exposure to light as indicated in the figure. After illumination 1 μg ml⁻¹ gelonin (gel) was added, and the cells were incubated for 18 h. For the ‘light after’ strategy the cells were co-incubated with 20 μg ml⁻¹ AlPcS_2a and 1 μg ml⁻¹ gelonin for 18 h before light exposure. The control cells were treated only with 1 μg ml⁻¹ gelonin for 18 h and exposed to light, or only with 20 μg ml⁻¹ AlPcS_2a for 18 h, chased 4 h in AlPcS_2a-free medium and exposed to light. [³H]leucine incorporation into proteins was measured the day after the light-treatment. Data presented are the mean relative to non-illuminated cells. Data points represent mean±s.e. of triplicates.