Abstract: The interaction between carboxymethylchitosan-Cr (III) Complex (CMC-Cr) and herring sperm DNA were investigated by cyclic voltammetry and UV-Vis spectra.The results indicated:Firstly,the peak current of probe molecule Fe(CN)₆^3-/^4- at Au/DNA electrodes obviously decreased and the peak potential shifted positively because of the existences of CMC-Cr,which showed that there was a competitive effect between CMC-Cr and Fe(CN)₆^3-/^4- with herring sperm DNA,and revealed that a binding mode intercalation was interacted between CMC-Cr and herring sperm DNA.Secondly,the absorption intensity of CMC-Cr/DNA system increased with the adding of neutral red (NR),the maximum absorption peak had a red shifted and appeared equal absorption point,which further illustrated that a binding mode intercalation was interacted between CMC-Cr and herring sperm DNA,thus led to the change of DNA conformation.The combining ratio of n(CMC-Cr) and n(DNA) was 3:1.

Key words: CMC-Cr, herring sperm DNA, cyclic voltammetry, UV-Vis spectrum, interaction