Tong Xiao-qing, Lü Jian-quan, Sun Juan, Gong Zhong-hong
Hubei Key Laboratory of Bioanalytical Technology, Hubei Normal University, Huangshi 435002, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2007 Dec;27(12):2538-41.
The inclusion of beta-cyclodextrin (CD) for thionine (TH) and the interaction of DNA with CD-TH inclusion complex were investigated by fluorescence and visible absorption spectrometry. TH with beta-CD formed a 1 : 1 inclusion complex with the stability constant of 527 L x mol(-1) (visible spectrometry)/444 L x mol(-1) (fluorescence) in the pH 7.2 PBS buffer solutions. The addition of DNA makes the absorbance of the inclusion complex decrease and the absorption spectrum shift toward long wavelengths. The fluorescence experiments indicated that the presence of DNA makes the emission peak of CD-TH shift toward short wavelengths and the fluorescence of inclusion complex quench, and the quenching constant was calculated to be 6.12 x 10(4) L x mol(-1) by Stern-Volmer method. All the data confirmed that CD-TH reacted with DNA in intercalative mode, and the binding numbers and the binding constant were estimated to be 1 and 3.47 X 10(4) L x mol(-1) by spectrophotometry.
采用荧光光谱法和可见吸收光谱法研究了β-环糊精（CD）对硫堇（TH）的包合作用以及DNA与CD-TH包合物的相互作用。在pH 7.2的磷酸盐缓冲溶液中，TH与β-环糊精形成1:1的包合物，其稳定常数通过可见光谱法测得为527 L·mol⁻¹，通过荧光光谱法测得为444 L·mol⁻¹。加入DNA后，包合物的吸光度降低，吸收光谱向长波长方向移动。荧光实验表明，DNA的存在使CD-TH的发射峰向短波长方向移动，包合物的荧光猝灭，通过Stern-Volmer方法计算得到猝灭常数为6.12×10⁴ L·mol⁻¹。所有数据证实CD-TH与DNA以插入模式反应，通过分光光度法估算结合数为1，结合常数为3.47×10⁴ L·mol⁻¹。
