曲酸与胰蛋白酶相互作用的光谱学研究

Studies on the interaction between kojic acid and trypsin by fluorescence spectrophotometry

研究了曲酸对胰蛋白酶活性的影响，以及曲酸处理的胰蛋白酶的紫外光谱、荧光淬灭光谱、同步荧光光谱和三维荧光光谱．结果显示曲酸对胰蛋白酶具有激活作用；二者相互作用后，曲酸可以使胰蛋白酶的紫外吸收强度增强，但却使得蛋白内源荧光强度下降．Stern—Volmer作图显示了曲酸对胰蛋白酶的荧光淬灭为静态淬灭作用，求出二者的结合常数K为5．30×10^7 L／mol，结合位点，2为1．50；用同步荧光光谱和三维荧光光谱探讨了曲酸对胰蛋白酶构象的影响．

The effects of kojic acid on trypsin activity, and the changes of ultraviolet spectroscopy, fluorescence spectra, synchronous fluorescence spectra, and three-dimensional fluorescence spectra of kojic acid-treated trypsin were studied. The results showed that treatment of trypsin by kojic acid resulted in the increasing of trypsin acitivty. Kojic acid treatment caused increasing of intensity of UV absorption of trypsin, while the intensity of intrinsic fluorescence of kojic acid-treated trypsin was decreased. The fluorescence quenching of trypsin by kojic acid is through static quenching as revealed by Stern-Volmer plots. The binding constant Kq of them was 1.42 × 10^12 L/mol ·s, and the binding site was 1.50. Also, synchronous fluorescence spectra and three-dimensional fluorescence spectra were applied to reveal the mechamism of conformational changes of trypsin caused by kojic acid.