UV-Vis spectroscopy, fluorescence spectroscopy, cyclic voltametry (CV), and viscosimetric methods were applied to investigate the mechanism of the interaction between melamine (MM) and herring sperm DNA. The effect of MM on the migration rate of pBR322 plasmid DNA was investigated by gel electrophoretic method as well. The results showed that for the system of pH at 7.0, the charge transfer coefficients (α) were 0.27 and 0.26, with the velocity constant (k_s) at 5.58 s^-1 and 5.65 s^－1 for the MM before and after DNA added, respectively. The interaction between MM and DNA may be realized via groove combined mode. The thermodynamic formulation constant (K) was ca. 10⁵ mol^－1•L.

Key words: melamine, herring sperm DNA, interaction mode, dynamic constant, thermodynamic formulation constant