Interaction between tryptophan-vanillin Schiff base and herring sperm DNA

摘要

The interaction of the Schiff base (K[HL]) with herring sperm DNA was studied by UV-vis absorption, fluorescence and viscosity methods in a physiological pH environment (pH 7.40), where the Schiff base was derived from vanillin and L-tryptophan. A binding ratio of nK[HL]:nDNA = 5:1 and an apparent molar absorption coefficient of εK[HL]-DNA = 4.98 × 105 L·mol-1·cm-1 were confirmed by the mole ratio method. The binding constants of KB ? 28°C = 1.94 × 105 L·mol-1 and KB ? 37°C = 1.09 × 105 L·mol-1 were obtained by the double reciprocal method. Thermodynamic parameters suggest that the interaction between K[HL] and DNA is driven mainly by enthalpy. Combined with Scatchard methods and viscosity methods, the results indicate the presence of intercalation and groove binding between K[HL] and DNA.