The interaction of lumichrome (LC) as an endogenous fluorescence probe with nucleobases,nucleosides and nucleic acids has been studied by UV-visible absorption,fluorescence spectroscopy,polarized fluorescence and viscosity. The fluorescence of LC was strongly quenched by a series of nucleic acids and their precursors. The influences of the medium,temperature and salt effects on LC-nucleobase and LC-nucleic acid complexes were investigated. The influences of polarized fluorescence,thermal denaturation and viscosity on LC-ctDNA interaction were examined. The results demonstrate that the main binding model of LC-ctDNA includes strong intercalating into the DNA helix chain.
