2种青稞多糖对胰α-淀粉酶的抑制作用  

Inhibitory Effects of Two Polysaccharides from Highland Barley on the Activity of Pancreaticα-Amylase

作　　者：李志鹏 周晨熠 潘书童 崔泽文 谢凡 王光强[1] 艾连中[1] 张汇[1] LI Zhipeng;ZHOU Chenyi;PAN Shutong;CUI Zewen;XIE Fan;WANG Guangqiang;AI Lianzhong;ZHANG Hui(Shanghai Engineering Research Center of Food Microbiology,School of Health Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学健康科学与工程学院,上海食品微生物工程技术研究中心,上海200093

出　　处：《食品科学》2023年第22期192-199,共8页Food Science

基　　金：上海市自然科学基金项目(20ZR1439100);上海市科技创新行动计划项目(21015800300)。

摘　　要：分别从青稞麸皮和胚乳中制备2种常见的谷物多糖青稞阿拉伯木聚糖(highland barley arabinoxylan,HBAX)和青稞β-葡聚糖(highland barleyβ-glucan,HBBG),通过酶促动力学和荧光猝灭分析研究了2种青稞多糖对胰α-淀粉酶的抑制作用、抑制方式、抑制类型及其与酶的相互作用关系。结果表明,HBAX和HBBG对胰α-淀粉酶均有一定的抑制作用,但HBAX的抑制作用显著强于HBBG;二者对胰α-淀粉酶的抑制方式均为可逆性抑制,但其抑制类型不同,HBAX为竞争性和非竞争性的混合型抑制,表明其不仅能与酶活性位点结合,还能形成酶-淀粉-抑制剂复合物阻碍酶促反应,而HBBG为反竞争性和非竞争性的混合型抑制,说明HBBG只能与酶的非活性位点结合形成酶-淀粉-抑制剂复合物。荧光猝灭结果证实HBAX和HBBG均能与胰α-淀粉酶发生相互作用,并通过静态猝灭其内源荧光,但HBAX与酶的亲和力显著高于HBBG,且HBAX能影响胰α-淀粉酶的内部疏水环境极性,从而影响其微观结构。综上,HBAX和HBBG对胰α-淀粉酶的抑制作用差异可能与其抑制类型和相互作用亲和力不同有关。本研究将为青稞多糖在淀粉消化调控和低血糖生成指数食物中的应用提供一定的理论依据。In this study,two common cereal polysaccharides,arabinoxylan(HBAX)andβ-glucan(HBBG),were prepared from the bran and endosperm of highland barley,respectively.The inhibitory effects,modes and types of the two polysaccharides on pancreaticα-amylase and their interactions with the enzyme were investigated by enzymatic kinetics and fluorescence quenching analysis.The results showed that both HBAX and HBBG effectively inhibited the activity of pancreaticα-amylase,the former being significantly more effective.Their inhibitory effects were both reversible,but their inhibitory types were different.HBAX presented mixed competitive and non-competitive inhibition,indicating that it not only can bind to the active sites of the enzyme,but also can form an enzyme-starch-inhibitor complex to block the enzymatic reaction.HBBG exhibited a mixed type of anti-competitive and non-competitive inhibition,suggesting that HBBG could only bind to the inactive sites of the enzyme to form an enzyme-starch-inhibitor complex.The fluorescence quenching results revealed that both HBAX and HBBG could interact with pancreaticα-amylase and quench its endogenous fluorescence statically.However,HBAX showed significantly higher affinity to the enzyme than HBBG,and could affect the polarity of the internal hydrophobic environment of pancreaticα-amylase,and in turn affect its microstructure.In conclusion,the differences in the inhibitory effects of HBAX and HBBG on the activity of pancreaticα-amylase might be related to their different inhibitory types and affinities to the enzyme.This study will provide a theoretical basis for the application of highland barley polysaccharides in the regulation of starch digestion and in low glycemic index foods.

关 键 词：青稞 阿拉伯木聚糖 Β-葡聚糖 胰α-淀粉酶 酶抑制动力学 荧光猝灭 

分 类 号：TS201.7[轻工技术与工程—食品科学]