Figure 4.

Photosensitization of α-crystallin by porphyrins in the presence of the singlet oxygen quencher azide and the radical spin trap/scavenger DMPO. Aliquots of α-crystallin containing 10 μM of the indicated porphyrin, and containing either no further additions or 10 mM NaN₃ or 200 mM DMPO or both, as indicated, were exposed to 40 min of UVA irradiation as described in the materials and methods. For each porphyrin three duplicate gels containing 13 μg of protein per lane were subjected to SDS-PAGE electrophoresis under reducing conditions. One gel was stained with Coomassie blue (top panels), and two were transferred to nitrocellulose for western blot analysis with anti-NFK (middle panels) and anti-DMPO (bottom panels) antisera