[Study on the non-covalent interaction of 7-hydroxy flavone and its phosphate with DNA by fluorescence method]

The non-covalent interaction of 7-hydroxy flavone and its phosphate with DNA was studied using ethidium bromide (EB)as a probe. The result showed that both 7-hydroxy flavone and its phosphate could form non-covalent complexes, but the phosphorylated flavonoid showed higher binding affinity with DNA than 7-hydroflavone did. Experiments demonstrated that the higher the temperature, the lower the slop of quenching curve of DNA-EB in the presence of different amounts of 7-hydroxy flavone and its phosphate. It was confirmed that the combinations of DNA with 7-hydroxy flavone and its phosphate were a single static quenching process. According to the Stern-Volmer equation and Scatchard equation the quenching constants and the intrinsic binding constants of 7-hydroxy flavone and its phosphate were measured respectively, they were Kq1 = 601 L x mol(-1), Kq2 = 1381 L x mol(-1); K1 = 2.07 x 10(4) L x mol(-1) , K2 = 3.19 x 10(4) L x mol(-1) respectively.