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目的研究模拟生理条件下中药活性组分左旋紫草素与胰蛋白酶的相互作用情况。方法本文利用荧光光谱法,研究了左旋紫草素与胰蛋白酶猝灭机制;根据Stern-Volmer和Scathard方程求得不同温度下左旋紫草素与胰蛋白酶相互作用的结合常数及结合位点数;并且利用Forster能量转移理论,求得两者间的键合距离。结果在温度为303、310、318 K时,测得两者相互作用的结合常数分别为1.84502×105、1.28896×105、0.74927×105/M及结合位点数分别为1.16106、1.12327、1.11062;同步荧光研究表明左旋紫草素与胰蛋白酶有着较强的结合,结合位置与色氨酸残基间的距离r为3.36 nm。结论左旋紫草素与胰蛋白酶有强的结合,左旋紫草素对胰蛋白酶的荧光猝灭机制为静态猝灭,并综合实验得到的结果,确定了二者间的作用力,结合位置与色氨酸残基间的距离r都小于7 nm(为3.36 nm)。
Objective To study the interaction between L-shikonin and trypsin in Chinese herbal medicine under simulated physiological conditions. Methods The fluorescence quenching mechanism of L-shikonin and trypsin was studied by fluorescence spectroscopy. The binding constants and binding sites of L-shikonin and trypsin at different temperatures were obtained according to the Stern-Volmer and Scathard equations. Using Forster energy transfer theory, find the bonding distance between the two. Results The binding constants of interaction between the two were 1.84502 × 105, 1.28896 × 105, 0.74927 × 105 / M and the number of binding sites were 1.16106, 1.12327 and 1.11062 at the temperature of 303, 310 and 318 K, respectively. Synchronous fluorescence Studies have shown that L-shikonin and trypsin have a strong combination, the binding position and the distance between tryptophan residues r is 3.36 nm. Conclusion L-shikonin has strong binding with trypsin, and the fluorescence quenching mechanism of L-shikonin to trypsin is static quenching. Based on the experimental results, the interaction between L-shikonin and trypsin is confirmed. The distance r between the amino acid residues is less than 7 nm (3.36 nm).