Oxygen-Independent Photocleavage of DNA, and Uptake of Chlorophyll Derivatives by Cellular Nuclei and Mitochondria

Abstract

Plasmid DNA has been efficiently photocleaved by sodium pheophorbides (Na-Phdes) a and b in the absence of oxygen as well as in the presence of oxygen. Singlet oxygen production sensitized by Na-Phdes a or b cannot be observed in the aqueous media, but with remarkable efficiency in organic solvents. Fluorescence microscopic observation has shown a rapid incorporation of Na-Phde a into nuclei, mitochondria, and lysosome of human oral mucosa cells. In contrast, Na-Phde b has been incorporated only into the plasma membrane. Fluorescence intensity of Na-Phde a has rapidly decreased during microscopic observation, indicating that some photochemical reactions take place in the organelle.