Interaction mode between methylene blue-Pr(III) complex and herring-sperm DNA

摘要

By spectroscopic method, the binding ratios between methylene blue-Pr(III) and DNA in physiological pH environment (pH=7.40) were determined as n _(Pr):n_(MB)(III)=1:3 and n_(Pr)(III)(MB)3:n _(DNA)=8:1. The binding constants at different temperatures K ~θ_(20°C)=7.14×10~5L·mol ~(-1) and K~θ_(37°C)=2.43×10 ~5L·mol~-1 were obtained by double reciprocal method. Thermodynamic function computation demonstrates that Δ_rH ~Θ_m is the primary driving power of the interaction between Pr(III)(MB)_3 and herring-sperm DNA. According to the analysis, we have evidenced that the interaction mode between Pr(III)(MB) _3 complex and herring-sperm DNA is partial intercalation binding.