To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV–vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculat...To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV–vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculations. The binding of CHE to cytidine could be characterized by the hypochromic and bathochromic effects in the absorption bands, and the quenching of fluorescence intensity. The spectral data were fit by linear analysis, yielding a binding constant of 2.49 × 10(4) L mol(?1)at 25 °C of CHE and cytidine, and a van’t Hoff enthalpy of ?20.02 kJ/mol for the exothermic interaction in the standard state. In addition, with and , the interactions should be entropy-driven.展开更多
The interaction between sanguinarine and guanosine was investigated by using UV-vis and fluorescence spectra at pH 7.2. The binding of sanguinarine to guanosine was substantiated by the hypochromism and bathochromism ...The interaction between sanguinarine and guanosine was investigated by using UV-vis and fluorescence spectra at pH 7.2. The binding of sanguinarine to guanosine was substantiated by the hypochromism and bathochromism in the absorption spectra and the emission quenching in fluorescence spectra. The fluorescence lifetime results, the varieties of the fluorophore absorption spectra and the decrease of the binding constant with the increasing temperature all indicate that the fluorescence quenching is static. The ratio and constant of the binding cytidine to sanguinarine are 2 and 6.44 × 10^7, respectively. The result shows that the binding of sanguinarine to guanosine is not only exothermic but also entropy-driven with △H=-8.53kJ/mol, AS = 0.12 kJ/（molK）, and AG =-44.57 kJ/mol at 298.15 K.展开更多
FTIR spectrum at liquid nitrogen temperature and IH NMR of air-sensitive polyhydride Ru(H)_2(H_2)(PPh_3)_3 have been measured for the first time. It is found that a fluxional process happens at room temperature, but t...FTIR spectrum at liquid nitrogen temperature and IH NMR of air-sensitive polyhydride Ru(H)_2(H_2)(PPh_3)_3 have been measured for the first time. It is found that a fluxional process happens at room temperature, but the structure of Ru(H)_2(H_2)(PPh_3)_3 with non-equivalent hydrogens is discernible at low temperature.展开更多
文摘To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV–vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculations. The binding of CHE to cytidine could be characterized by the hypochromic and bathochromic effects in the absorption bands, and the quenching of fluorescence intensity. The spectral data were fit by linear analysis, yielding a binding constant of 2.49 × 10(4) L mol(?1)at 25 °C of CHE and cytidine, and a van’t Hoff enthalpy of ?20.02 kJ/mol for the exothermic interaction in the standard state. In addition, with and , the interactions should be entropy-driven.
文摘The interaction between sanguinarine and guanosine was investigated by using UV-vis and fluorescence spectra at pH 7.2. The binding of sanguinarine to guanosine was substantiated by the hypochromism and bathochromism in the absorption spectra and the emission quenching in fluorescence spectra. The fluorescence lifetime results, the varieties of the fluorophore absorption spectra and the decrease of the binding constant with the increasing temperature all indicate that the fluorescence quenching is static. The ratio and constant of the binding cytidine to sanguinarine are 2 and 6.44 × 10^7, respectively. The result shows that the binding of sanguinarine to guanosine is not only exothermic but also entropy-driven with △H=-8.53kJ/mol, AS = 0.12 kJ/（molK）, and AG =-44.57 kJ/mol at 298.15 K.
文摘FTIR spectrum at liquid nitrogen temperature and IH NMR of air-sensitive polyhydride Ru(H)_2(H_2)(PPh_3)_3 have been measured for the first time. It is found that a fluxional process happens at room temperature, but the structure of Ru(H)_2(H_2)(PPh_3)_3 with non-equivalent hydrogens is discernible at low temperature.
