摘要
The Interaction between vitamin B12 （VBI2） and fish sperm DNA was investigated in physiological buffer （pH 7.4） using the methylene blue （MB） dye as a spectral probe by spetcrophotometery, viscosity measurements and cyclic voltammetry. The apparent binding constant of vitamin B12 with DNA was found to be 3.2 × 10^5 mol^-1·L. The voltammetric behavior of vitamin B12 has been investigated at glassy carbon electrode using cyclic voltammetry. Thermodynamic parameters including △H^0, △S^0 and △G^0 for the interaction between VB12 and DNA have determined as -2.3 × 10^4, 27.54 and -3.1 × 10^4j·mol^-l·K^-1 respectively. One indication of DNA binding mode with VBI2 was the change in viscosity when a small molecule associates with DNA. The diffusion coefficients of VB12 in the absence （D0）f and presence of DNA （D0）b was calculated as 5.04 × 10^-6 and 1.13 × 10^-6 cm^2·s^-1 respectively. The results indicated that vitamin B12 can bind to DNA and the major binding mode was intercalative binding.
The Interaction between vitamin B12 （VBI2） and fish sperm DNA was investigated in physiological buffer （pH 7.4） using the methylene blue （MB） dye as a spectral probe by spetcrophotometery, viscosity measurements and cyclic voltammetry. The apparent binding constant of vitamin B12 with DNA was found to be 3.2 × 10^5 mol^-1·L. The voltammetric behavior of vitamin B12 has been investigated at glassy carbon electrode using cyclic voltammetry. Thermodynamic parameters including △H^0, △S^0 and △G^0 for the interaction between VB12 and DNA have determined as -2.3 × 10^4, 27.54 and -3.1 × 10^4j·mol^-l·K^-1 respectively. One indication of DNA binding mode with VBI2 was the change in viscosity when a small molecule associates with DNA. The diffusion coefficients of VB12 in the absence （D0）f and presence of DNA （D0）b was calculated as 5.04 × 10^-6 and 1.13 × 10^-6 cm^2·s^-1 respectively. The results indicated that vitamin B12 can bind to DNA and the major binding mode was intercalative binding.
