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在模拟生理pH条件下,采用荧光光谱、紫外-可见吸收光谱、同步荧光光谱和圆二色谱法研究木犀草素及槲皮素与牛血清白蛋白(BSA)的相互作用的异同。结果确定木犀草素及槲皮素对BSA的荧光猝灭是以静态猝灭为主,同时伴随非辐射能量转移猝灭。木犀草素结合BSA的位点与荧光发射基团的距离比槲皮素的小。结合常数K a表明二者与BSA的结合都属于强的非共价键结合,且结合位点数都约为1。二者均主要通过氢键和范德华力与BSA作用。二者都能影响BSA的酪氨酸残基附近环境的极性,且高浓度下能够引起BSA构象轻微地改变。结果表明黄酮C环上3位羟基的引入会降低其对BSA的亲和力。
The similarities and differences of interaction between luteolin and quercetin with bovine serum albumin (BSA) were studied by fluorescence spectroscopy, UV-vis absorption spectroscopy, synchronous fluorescence spectroscopy and circular dichroism spectroscopy at simulated physiological pH. Results The fluorescence quenching of BSA by luteolin and quercetin was mainly determined by static quenching, accompanied by quenching by non-radiative energy transfer. The luteolin-BSA-binding site has a smaller distance from the fluorescent emitting group than quercetin. The binding constant K a indicates that both of them bind to BSA strong non-covalent bond, and the number of binding sites is about one. Both interact primarily with BSA via hydrogen bonding and van der Waals forces. Both can affect the polarity of the environment near the tyrosine residues of BSA and can cause a slight change in BSA conformation at high concentrations. The results show that the introduction of the hydroxyl group at the 3 position on the C ring of flavone decreases its affinity for BSA.