Abstract
A water-soluble mercury(II) porphyrin was used as a photosensitizer in DNA cleavage. The nuclease activity of the sensitizer at subnanomolar concentration was investigated by the conversion of supercoiled (F-I) pBluescript plasmid DNA to open circular (F-II), linear (F-III) and small fragments DNA upon photoirradiation. The results indicated that the photocleavage of DNA was dependent on the concentration of sensitizer and irradiation time. Hydroxyl radical (•OH) and singlet oxygen (1O2) promoted DNA photocleavage. The formation of these active species during DNA photocleavage reaction was confirmed by the inhibitory effect of active oxygen scavengers and as well as by ESR measurement.
