Assembling Zwitterionic, Water-Soluble Porphyrin And Its Biological Studies

Electric charge is one of the most vital facts that affect the chemical, physical and biological activities of porphyrins. Ether negative charge or positive charge has its own properties in the biological activities of porphyrins. So the combination of both negative charge and positive charge on the porphyrin ring may bright better properties comparing with only negative or positive charge. A kind of zwitterionic water - soluble porphyrin ?5 - (N~ trimethyl- 4- aminiumphenyl) - 10, 15, 20-tri (4- sulfonatephenyl) porphyrin trisammonium salt (16) has been synthesized, and its biological activities were investigated. The results were shown blow:1.The positive charge can improve the affinity of porphyrin to DNA. In the DNA cleavage experiment, zwitterionic water-soluble porphyrin (16) has more stronger ability to cleavage DNA than that of tetrasulfonatephenyl porphyrin (17) with four negative charges. At low pH, positive charge on the inner nitrogen atoms also can improve the affinity of porphyrin to DNA.2. The zwitterionic porphyrin (16) has the stronger ability to kill Gram' bactieria than that of the porphyrin (17) only with negative charge. The cell wall can be destructed badly by zwitterionic porphyrin, when it was observed by AFM (Atomic Force Microscope). So the more severe destroy of cell wall may be the significant reason of the stronger ability to kill Gram" bactieria of zwitterionic porphyrin.3. The zwitterionic porphyrin (16) that was synthesized by us has the similar capability to destroy tumor cells as that of tetrasulfonatephenyl porphyrin (17) just with four negative charges.4. This zwitterionic porphyrin (16) with one positive charge has the weaker affinity to bovine serum albumin than that of tetrasulfonatephenyl porphyrin (17) so the positive charge might decrease the affinity of porphyrin to some protein.