文献类型：期刊文献

英文题名：Property of Midgut α-Amylase From Mythimna separata (Lepidoptera: Noctuidae) Larvae and Its Responses to Potential Inhibitors In Vitro

作者：Xu, Wenping[1];Huang, Qingchun[1];Wu, Xiwei[1];Yu, Xiaoqin[1];Wang, Xuexiao[1];Tao, Liming[1]

机构：[1]E China Univ Sci & Technol, Sch Pharm, Shanghai Key Lab Chem Biol, Shanghai 200237, Peoples R China

年份：2014

卷号：14

外文期刊名：JOURNAL OF INSECT SCIENCE

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000349770200121)】；

基金：This work was supported by the National Key Project for Basic Research (2010CB126101). We are grateful to Professor Larry Murdock from Purdue University, IN, for English improvement.

语种：英文

外文关键词：midgut alpha-amylase; Mythimna separata; chemical inhibitor

摘要：Midgut alpha-amylase is an important digestive enzyme involved in larval energy metabolism and carbohydrate assimilation. In this article, the properties of midgut alpha-amylase from the Oriental armyworm, Mythimna separata (Lepidoptera: Noctuidae), larvae were characterized, and its in vitro responses to chemical inhibitors were also determined. The kinetic parameters K-m and V-max of midgut alpha-amylase were 0.064M, 4.81 U mg pro(-1) in phosphate buffer, and 0.128M, 1.96 U mg pro(-1) in barbiturate-acetate buffer; alpha-amylase activity linearly increased as starch concentration increased. alpha-Amylase activity was not influenced by amino acids such as Pro, Met, Try, His, Ala, and Phe but was strongly activated by antioxidants. Reduced glutathione, 1,4-dithiothreitol, beta-mercaptoethanol, and ascorbic acid improved the activity of alpha-amylase about 2.06, 3.46, 3.37, and 6.38 times, respectively, relative to the control. Ethylenediaminetetraacetic acid, sodium dodecyl sulfonate, and N-bromosuccinimide (NBS) strongly inhibited alpha-amylase. alpha-, beta-, and gamma-cyclodextrin were not the preferred substrates for alpha-amylase. Kinetic analysis showed that IC50 value of NBS against alpha-amylase was 1.52 (+/- 0.26) mu M, and the mode of action of NBS with K-i as 2.53 (0.35) mu M was a mixed-type inhibition that indicated a combination of partial competitive and pure noncompetitive inhibition. The midgut alpha-amylase of armyworm larvae may be a potential target for novel insecticide development and pest control.