Photo-oxidation of cells generates long-lived intracellular protein peroxides

摘要: Singlet oxygen is generated by several cellular, enzymatic, and chemical reactions as well exposure to UV or visible light in the presence of a sensitizer. Consequently, this oxidant has been proposed be damaging agent many pathologies. Proteins are major targets for singlet result their abundance high rate constants reaction. In study, we show that illumination viable rose bengal-loaded THP-1 (human monocyte-like) cells with gives rise intracellular protein-derived peroxides. The peroxide yield increases time, requires bengal, enhanced D(2)O, decreased azide, consistent mediation oxygen. concentration peroxides detected, which not affected glucose ascorbate loading cells, corresponds about 1.5 nmoles per 10(6) 10 nmoles/mg cell protein, account up approximately 15% O(2) consumed cells. Similar have detected on isolated cellular proteins exposed bengal After cessation illumination, protein levels decrease t(1/2) 4 h at 37 degrees C. Decomposition formed within proteins, metal ions radicals EPR spin trapping. These studies demonstrate intact sensitizer leads novel long-lived, but reactive, via oxygen-mediated reactions.