Adriamycin-Fe3+-induced mitochondrial protein damage with lipid peroxidation.

Exposure of mitochondria to adriamycin (ADM)-Fe3+ induced formation of thiobarbituric acid reactive substances and fluorescent substances. Butylated hydroxytoluene (BHT) and the water soluble vitamin E analogue, trolox, not only strongly inhibited fluorescence formation but also mitochondrial lipid peroxidation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated the formation of high molecular weight proteins when mitochondria were exposed to ADM-Fe3+. A mitochondrial protein with a molecular weight of approximately 30 kDa was very sensitive to ADM-Fe3+. BHT and trolox strongly inhibited mitochondrial protein cross-linking, indicating that the protein modification was due to ADM-Fe(3+)-induced lipid peroxidation. In addition, the susceptibility of ADM-Fe(3+)-exposed mitochondrial protein to proteases was unchanged. Bovine serum albumin (BSA) inhibited ADM-Fe(3+)-induced mitochondrial lipid peroxidation. Fluorescence emmited from BSA was detected during ADM-Fe(3+)-induced mitochondrial lipid peroxidation, and BHT strongly inhibited the oxidative modification of BSA. These results suggest that the oxidative modification of mitochondrial proteins and BSA is due to ADM-Fe(3+)-induced lipid peroxidation.