Interactions of Cytochrome c with DNA at glassy carbon surface

Cyclic voltammetry (CV) was used to investigate the interactions of Cytochrome c (Cyt c) with deoxyribonucleic acid (DNA) at glassy carbon (GC) electrodes. The results indicate that there are strong interactions between Cyt c and DNA. The binding constant (kA) and binding free energy (ΔrG) of Cyt c with dsDNA are (1.69 ± 0.38) × 105 L·mol− 1 and − (29.76 ± 0.56) kJ·mol− 1, respectively; and those of Cyt c with ssDNA are (3.35 ± 0.50) × 105 L·mol− 1 and − (31.49 ± 0.37) kJ·mol− 1, respectively. The binding sites are achieved to be 3.3 bp per Cyt c molecule with dsDNA and 4.0 nucleotides (ssDNA) binding one Cyt c molecule. This experiment affords a valid method for investigating the interactions between DNA and proteins by electrochemical techniques.