Laboratory of Enzymology - LABENZ, Department of Biochemistry, Federal University of Pernambuco, Brazil.
Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Denmark; School of Food Science and Engineering, South China University of Technology, Guangzhou, China.
Food Chem. 2021 Aug 30;354:129513. doi: 10.1016/j.foodchem.2021.129513. Epub 2021 Mar 9.
A raw starch digesting α-amylase from Nile tilapia (Oreochromis niloticus) intestine was identified. The α-amylase, AMY-T, had an estimated molecular weight of 60 kDa and purified to near homogeneity. AMY-T showed an apparent K 4.78 mg/mL and V 0.44 mg/mL/min) towards soluble starch. It was highly stable for 24 h in the pH range 3.0-10.0, and to solvents like methanol, isopropanol, butanol, dimethylformamide, DMSO and ethyl-ether. AMY-T was able to digest different carbohydrates, mainly showing endo-activity. Importantly, AMY-T was catalytically efficient and adsorbing towards raw potato starch at temperature documented for other raw starch digesting α-amylases. Thin layer and anion exchange chromatography characterization showed that the end products of raw starch hydrolysis were glucose, maltose and maltodextrins, with degree of polymerisation ranging 1-8. Scanning electron microscopy analysis of the AMY-T treated starch granules documented both granular exo- and endo-attack by AMY-T. These catalytic capabilities suggest high potential for AMY-T for industrial use.
从尼罗罗非鱼（Oreochromis niloticus）肠道中鉴定出一种原始淀粉消化α-淀粉酶（AMY-T）。该α-淀粉酶的分子量约为 60 kDa，并被纯化至近乎均一。AMY-T 对可溶性淀粉的表观 K m 值为 4.78 mg/mL，V max 值为 0.44 mg/mL/min。它在 pH 值 3.0-10.0 范围内稳定 24 小时，并能耐受甲醇、异丙醇、正丁醇、二甲基甲酰胺、DMSO 和乙醚等溶剂。AMY-T 能够消化不同的碳水化合物，主要表现出内切酶活性。重要的是，AMY-T 在其他原始淀粉消化α-淀粉酶记录的温度下对生土豆淀粉具有催化效率和吸附作用。薄层和阴离子交换色谱分析表明，生淀粉水解的终产物是葡萄糖、麦芽糖和麦芽糊精，聚合度为 1-8。对 AMY-T 处理的淀粉颗粒的扫描电子显微镜分析记录了 AMY-T 对淀粉颗粒的颗粒外切和内切攻击。这些催化能力表明 AMY-T 具有很高的工业应用潜力。
