Light Scattering and Viscosimetric Studies on DNA after the Photoreaction with Some Furocoumarins

Abstract

The light scattering measurements and the viscosimetric “i-assay” performed on native DNA solutions before and after irradiation at 3655 Å in the presence of furocoumarins show that the C₄-cycloadditions of furocoumarins to the 5,6-double bond of the pyrimidine bases of DNA, which take place in the photoreactions, produce neither breakages of the polynucleotide chains nor relevant modifications of the macromolecule conformation.