利复星与人血清白蛋白作用的荧光光谱研究

用荧光光谱研究了药物利复星(Levofloxacin)与人血清白蛋白(HSA)的作用和影响，测量发现人血清白蛋白的最大激发峰位于286.70 nm处。在向该溶液滴加Levofloxacin时，原有的343.70 nm发射峰强度明显减弱, 且向长波长稍有移位，并出现了位于503.96 nm的新荧光发射峰(利复星的发射峰), 利复星对HSA荧光有猝灭作用。利复星Levofloxacin的503.96 nm荧光的激发峰则位于300.16和336.16 nm。当向该溶液滴加利复星时，300.16和336.16 nm的激发峰仅向长波长方向稍有移动。利复星对HSA的离解常数K_d=3.65×10-5(mol·L-1)。利复星的结合常数为K_S=2.742×104(L·mol-1)。利复星-HSA体系的猝灭过程不是因为分子扩散和碰撞所引起的动态猝灭，而是分子之间结合形成了化合物所引起的静态猝灭。利复星对HSA的能量转移效率为E=0.372, 利复星和人血清白蛋白的色氨酸残基的结合位置为R=1.933 nm。

Fluorescence Spectroscopy Study of Humen Serum Albumin Quenched by Levofloxacin

The fluorescence spectroscopy of humen serum albumin (HSA) and the interaction of HSA and the Levofloxacin were studied. When the Levofloxacin was added into HSA solution gradually, an interesting new phenomenon emerged in emission spectrum peak. The intensity of 343.70 nm emission peak of HSA decreased obviously and moved towards long-wavelength, which is atypical quenching phenomenon. It was found that the excitation peak of HSA was positioned at 286.70 nm also. A new emission peak emerged at 503.96 nm, which resulted from the Levofloxacin. The excitation peaks of 503.96 nm fluorescence of Levofloxacin were positioned at 300.16 nm and 336.16 nm. When Levoflaxasin was added into HSA gradually, the 300.16 nm and 336.16 nm excitation peaks moved towards long wavelength. The dissociation constant of Levofloxacin from HSA is about Kd = 3.65 x 10(-5) (mol x L(-1)). The combination constant of Levofloxacin is about Ks = 2.742 x 10(4) (L x mol(-1)). The quenching process of Levofloxacin-HSA is not dynamic quenching, which resulted from the molecular diffusion and collision. It is caused by the static quenching process resulting from the chemical component between molecules. The energy transfer efficiency between Levofloxacin and HSA is E = 0.372. According to these calculation results, the combination position between the binding site of Levofloxacin and the tryptophane of HSA is about R = 1.933 nm.