Figure 5. Effects of singlet oxygen ‘quenchers’ on pro-apoptotic ability of reduced cyt c.

Cyt c in PBS was first oxidized and treated with 1 mM MNPE or the control condition (CTR) in the presence of 20 mM NaN₃, 20 mM histidine, 5 mM DABCO or 10 μM β-carotene at 37 °C for 1 h. After gel filtration of cyt c on the PD10 column, caspase activity was measured in a cell-free reconstitution system. Data represent relative activities of caspase-9 and -3 to control experiments that were performed with fully oxidized cyt c (CTR).