Author
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Johnson, William |
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THOMAS, ANN - UNIV OF NORTH DAKOTA |
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Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only Publication Acceptance Date: 4/6/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: The activities of respiratory complex I (assayed as NADH-cytochrome c reductase), complex II-III (assayed as succinate cytochrome c reductase), complex IV (assayed as cytochrome c oxidase), and citrate synthase were measured in mitochondria obtained from HL-60 cells grown for 9 passages in serum-free medium that was either unsupplemented or supplemented with 50 nM CuSO4. When corrected for citrate synthase activity, cells grown in the absence of supplemental copper had lower activities for complexes I, II-III, and IV (P<0.05, ANOVA) than cells grown in the presence of Cu. This indicates that Cu deprivation in these cell caused a general decline not only in complex IV, which contains Cu, but also in complexes II-III and I which do not contain Cu. Western blot immunoassay for phenylhydrazine derivatives of protein carbonyl groups, an indicator of oxidative damage, showed that the carbonyl content was increased in several whole cell and mitochondrial proteins when the cells were deprive of Cu. Mn-SOD content was also increased 75% (P<0.05, ANOVA) overall in cells deprived of Cu. These findings indicate that HL60 cells and their mitochondria experience oxidative stress when deprived of Cu for several passages. They also suggest that the reduction in complex II-III and complex I activities during Cu deprivation may result from oxidative damage caused by increased mitochondrial production of oxygen radicals when complex IV activity is decreased. |
