大黄三种有效成分对胰蛋白酶活性及结构的影响

The effect of three effective components of rhubarb on activity and structure of trypsin

大黄素、大黄酸、大黄酚对胰蛋白酶活性均有一定程度的抑制作用.当有效成分浓度为2.5 mg·L^(-1)时,长濑法测定表明它们对胰蛋白酶的抑制率分别为38.0%、48.2%及35.4%.紫外吸收光谱、荧光光谱和圆二色谱研究表明三种有效成分影响胰蛋白酶酪氨酸、色氨酸和苯丙氨酸残基的微环境,改变了胰蛋白酶结构.圆二色谱计算发现,大黄素、大黄酸、大黄酚分别使胰蛋白酶二级结构中α-螺旋含量减少了2.8%、3.2%和2.5%,β-折叠含量增加了1.6%、2.0%和1.4%.

Emodin, rhein and chrysophanol could inhibit the activity of trypsin in different levels. The inhibition ratio of emodin, rhein and chrysophanol to trypsin was measured through Nagase Method, and the inhibition ratio was 38.0%, 48.2% and 35.4% respectively when the concentration of these components was 2.5 mg·L-1. The effects of three effective components on structures of trypsin were studied through UV-absorption spectra, fluorescent spectra and circular dichroism spectrum. The results showed that three effective components could change the structure of trypsin and the microenvironment of Try, Tyr and Phe in trypsin. The content of α-helix decreased by 2.8%, 3.2 % and 2.5% and the content of β-fold increased by 1.6%, 2. 0% and 1.4% when the concentration was 2.5 mg·L-1.