SPECTROSCOPIC STUDIES ON THE INTERACTIONS OF WATER-SOLUBLE PORPHYRINSWITH NUCLEIC-ACIDS

This paper presents the spectroscopic features of the interactions of two porphyrins, meso-tetrakis (4-trimethylaminoniumphenyl)porphine(TAP P) and meso-tetrakis(N-methyl-4-pyridiniumyl)porphyrin (TMpyP-4) with nucleic acids. Spectra involve electron absorption, fluorescence and r esonance light-scattering. The studies of absorption and fluorescence show that the two porphyrins share common features when they interact with nucleic acids. That is, when the molar ratio of porphyrins to nuc leic acids, R>O.25, nucleic acids have hypochromicity and fluorescence quenching effect on the Soret bands of the two porphyrins; when R<O.2 5, new fluorescent products are formed. The difference of the interact ions of the two porphyrins with nucleic acids can be distinguished by resonance light-scattering spectra. Nucleic acids can strongly enhance the intensity of resonance light-scattering of TAPP, but not of TMpyP -4.