Thermodynamic Profile of Interaction of Porphyrins With Nucleic Acids

Abstract

Abstract:The binding of a number of novel water soluble porphyrins to nucleic acids (NA) were studied monitoring the changes in Soret region of absorbance spectra, fluorescence spectra and circular dichroism (CD) spectra of formed complexes. The binding modes for all complexes were dtermined. The binding isotherms were used to calculate the binding constant, K b , and binding free energy, G b = -RTlnK b . By performing these experiments as a function of temperature, we evaluated the van't Hoff binding enthalpies, H b and the binding entropies, S b . Generalization concerning the established correlation between the binding mode and thermodynamic profile was done.