荧光光谱法研究拜复乐与小牛胸腺DNA的作用机理

用荧光光谱法研究了拜复乐（MXFX）与小牛胸腺DNA（ctDNA）之间的相互作用。在pH=7.4的Tris-HCl缓冲溶液中，MXFX的荧光激发峰和发射峰分别位于291 nm和462 nm。ctDNA的加入对MXFX的荧光有静态猝灭作用，这种荧光静态猝灭作用是由ctDNA和MXFX结合引起的，作用力为氢键或范德华力，结合常数为1.28×10⁵ L/mol（25 ℃）。采用离子强度的影响、碘离子猝灭及溴乙锭竞争作用实验研究了MXFX与ctDNA间的相互作用，结果表明MXFX与DNA的结合是MXFX嵌入到DNA中相邻2个碱基对之间，属于嵌入结合模式。

Studies on The Interaction Mechanism Between Moxifloxacin and ctDNA by Fluorescence Spectroscopy

The interaction machanism of moxifloxacin (MXFX) and ctDNA was investigated by fluorescence spectroscopy. In Tris-HCl buffer solution of pH=7.40, the excitation and emission wavelengths of MXFX are 291 nm and 462 nm, respectively. The fluorescence of MXFX can be quenched by adding ctDNA, which is initiated by conjugation reaction between ctDNA and MXFX. The binding constant of this binary system is 1.28×10⁵ L/mol (25 ℃), and hydrogen bond or Van der Waals force play an important role on the conjugation reaction between ctDNA and MXFX. In addition, three experiments (effect of ionic strength, quenching experiment of I^－, and the competition of EB) results indicate that the conjugation mechanism can be considered as MXFX embedding into two adjacent base-pairs of ctDNA.