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 (k(A)) and binding free energy (Delta(r)G) of Cyt c with dsDNA are (1.69+/-0.38) x 10(5) L.mol(-1) and -(29.76+/-0.56) kJ.mol(-1), respectively; and those of Cyt c with ssDNA are (3.35+/-0.50) x 10(5) 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.