The interactions of nicotine and Hb/SA were studied in vitro by UV/Vis, fluorescence, 1H NMR and FT-IR spectroscopies. The UV/Vis absorbance of Hb/SA (200nm) shifted to red and decreased gradually with the addition of...The interactions of nicotine and Hb/SA were studied in vitro by UV/Vis, fluorescence, 1H NMR and FT-IR spectroscopies. The UV/Vis absorbance of Hb/SA (200nm) shifted to red and decreased gradually with the addition of nicotine, indicating that the protein conformational change resulted from the chemical interaction. With increasing nicotine concentration, incubation of SA with nicotine caused the quenching of fluorescence typical of protein tryptophan residues, which meant that the vicinity of the tryptophan residues of SA was changed because of nicotine. FT-IR spectra showed that α-helix component of Hb/SA decreased, turn and β-structure components of Hb/SA increased in the presence of nicotine. In the 1H NMR spectra of nicotine, all proton peaks on pyrrolidinyl ring moved to downfield and the resonance emanating from nicotine was preferentially broadened while the concentration of Hb/SA increased. All these results indicate that nicotine and Hb/SA in vitro interact on each other, forming a new展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 19935020)the Research Fund for Doctoral Program of Higher Education of China.
文摘The interactions of nicotine and Hb/SA were studied in vitro by UV/Vis, fluorescence, 1H NMR and FT-IR spectroscopies. The UV/Vis absorbance of Hb/SA (200nm) shifted to red and decreased gradually with the addition of nicotine, indicating that the protein conformational change resulted from the chemical interaction. With increasing nicotine concentration, incubation of SA with nicotine caused the quenching of fluorescence typical of protein tryptophan residues, which meant that the vicinity of the tryptophan residues of SA was changed because of nicotine. FT-IR spectra showed that α-helix component of Hb/SA decreased, turn and β-structure components of Hb/SA increased in the presence of nicotine. In the 1H NMR spectra of nicotine, all proton peaks on pyrrolidinyl ring moved to downfield and the resonance emanating from nicotine was preferentially broadened while the concentration of Hb/SA increased. All these results indicate that nicotine and Hb/SA in vitro interact on each other, forming a new
