title: Self-aggregation inhibits the photonuclease activity of porphyrins.
abstract: A series of tentacle porphyrins having four aminoalkyl groups at the periphery was synthesized, and the DNA binding properties were investigated by absorption and circular dichroism (CD) spectroscopic methods. The aminopropyl chain was found to facilitate binding, and bisignate induced CD spectra revealed that the porphyrins are self-stacked on the DNA surface. The photonuclease activity of the tentacle porphyrins was also studied, and the aminopropylporphyrin showed the highest activity. The activity increased in proportion to the porphyrin load, but higher loads resulted in the decrease of activity. This inhibitory step corresponded to aggregation of the porphyrin. Thus, the aggregation was suggested to shield the inner porphyrin from the solvent, the production of active oxygen species being suppressed.
authors.affiliation: Faculty of Pharmaceutical Sciences, Kumamoto University, Oehonmachi, Kumamoto 862-0973, USA.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Aoki
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Miyuki
authors.initials: M
authors.lastname: Oyama
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Tomisugi
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Uno
mesh_terms: D004247:DNA / Q000037:antagonists & inhibitors / Q000378:metabolism; D003851:Deoxyribonucleases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017319:Photosensitizing Agents / Q000037:antagonists & inhibitors / Q000378:metabolism; D011166:Porphyrins / Q000138:chemical synthesis* / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; D004247:DNA; D003851:Deoxyribonucleases