The influence of peripheral substituents on interaction of porphyrins with DNA

The interaction of meso-tetra-(3N-pyridyl)porphyrins with different peripheral substituents was studied by methods of spectrophotometry and circular dichroism. It was shown that for less concentration these porphyrins bind to DNA preferably via intercalation. The binding constants ($K_b$) and the number of binding sites per base pairs ($n$) were calculated by Correia and co-authors’ method.