“Pre-incubation of the cells with the MPO-specific inhibitor 4-aminobenzoic acid hydrazide (ABAH) and the heme enzyme inhibitor 3-aminotriazole (100 μM each) resulted in complete and partial inhibition, respectively, of intracellular MPO, caspase-3 activity, and apoptosis following addition of 50 μM H2O2.”