Fig. 31.3.

A2E-mediated photooxidation inactivates the proteasome in cultured RPE. Confluent cultured ARPE-19 cells were loaded with 10 µM A2E for 14 days. The cells were then transferred to PBS and exposed to blue light for 15 min and harvested. Cells that accumulated A2E alone, exposed to blue light alone, or neither accumulated A2E nor exposed to blue light were used as control. The chymotrypsin-like activity and trypsin-like activity of the proteasome in the cells were determined using a fluorogenic peptide as a substrate. The proteasome activity was expressed as increase in the relative fluorescence unit ( RFU) during a 5 min period. The experiments were repeated twice with triplicates each time. The data are mean ± SD of the results from 6 samples in each group. * indicates p < 0.001 as compared the control cells