没食子酸对α-淀粉酶和α-葡萄糖苷酶的抑制作用及机理  

Inhibitory Effect and Mechanism of Gallic Acid onα-Amylase andα-Glucosidase Activities

作　　者：沈荷玉 李梦阳 敖婧芳 王军[1] 徐怀德[1] 罗安伟[1] SHEN Heyu;LI Mengyang;AO Jingfang;WANG Jun;XU Huaide;LUO Anwei(College of Food Science and Engineering,Northwest A&F University,Yangling 712100,China)

机构地区：[1]西北农林科技大学食品科学与工程学院,陕西杨凌712100

出　　处：《食品科学》2023年第22期31-38,共8页Food Science

基　　金：“十三五”国家重点研发计划重点专项(2019YFD1002404)。

摘　　要：从抑制率、抑制动力学、紫外光谱、荧光光谱、圆二色谱及分子模拟方面研究没食子酸对α-淀粉酶和α-葡萄糖苷酶的抑制作用和机理。结果表明,没食子酸对α-淀粉酶和α-葡萄糖苷酶有良好的抑制效果,半数抑制浓度分别为(0.72±0.01)mmol/L和(0.59±0.02)mmol/L,以非竞争方式抑制α-淀粉酶,以混合竞争方式抑制α-葡萄糖苷酶。紫外光谱和荧光猝灭实验的结果表明,没食子酸通过改变α-淀粉酶和α-葡萄糖苷酶芳香族氨基酸残基周围的微环境,从而静态猝灭酶的荧光特性。圆二色谱分析表明,没食子酸能减少α-淀粉酶和α-葡萄糖苷酶的α-螺旋结构含量,增加β-折叠、β-转角和无规卷曲结构含量,从而改变酶构象。分子对接结果显示没食子酸与α-淀粉酶和α-葡萄糖苷酶的结合主要是通过氢键和疏水相互作用。In this study,the inhibitory effect and mechanism of gallic acid onα-amylase andα-glucosidase were investigated in terms of inhibitory rates,inhibition kinetics,ultraviolet(UV)spectra,fluorescence spectra,circular dichroism(CD)spectra,and molecular simulation.The results showed that gallic acid had a good inhibitory effect onα-amylase andα-glucosidase,with half maximum inhibitory concentrations(IC50)of(0.72±0.01)and(0.59±0.02)mmol/L,respectively,and inhibitedα-amylase in a non-competitive manner andα-glucosidase in a mixed competitive-non-competitive manner.The results of UV spectroscopy and fluorescence quenching indicated that gallic acid statically quenched the fluorescence of the enzymes by altering the microenvironment around their aromatic amino acid residues.CD spectroscopy showed that gallic acid reduced theα-helix content and increased theβ-sheet,β-turn and random coil contents ofα-amylase andα-glucosidase,thus leading to changes in the enzymes’conformation.The molecular docking results showed that gallic acid bound toα-amylase andα-glucosidase mainly through hydrogen bonds and hydrophobic interactions.

关 键 词：Α-淀粉酶 Α-葡萄糖苷酶 抑制作用 光谱 分子对接 

分 类 号：TS201.4[轻工技术与工程—食品科学]