Albalawi Karma M, Abdelrahman Ehab A, Rehman Khalil Ur, Alissa Mohammed, Alghamdi Abdullah, Alshehri Mohammed A, Alghamdi Suad A, Binshaya Abdulkarim S, Alhamzani Abdulrahman G, El-Sayyad Gharieb S
Department of Chemistry, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia.
Department of Chemistry, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia.
Bioorg Chem. 2025 Aug 18;164:108883. doi: 10.1016/j.bioorg.2025.108883.
This study reports the production, purification, and characterization of a thermostable, raw starch-hydrolysing α-amylase from Avena fatua seeds. The enzyme was purified to a 16.5-fold increase in purity through a series of steps, including pH adjustment, lyophilization, PEG precipitation, and multiple chromatographic techniques, ultimately achieving a specific activity of 90 U/mg. SDS-PAGE analyses confirmed the enzyme's purity and monomeric structure, with a molecular weight of approximately 29 kDa. The enzyme showed high stability at 4 °C, with a half-life of 90 days, extended to 121 days with acetaminophen. Kinetic values included K of 0.5 mM, V of 119 μmol/min/mg of protein, and kcat of 335 s. Activity was enhanced by Co, Ca, Mg, Ni, NH₄, NAD, glycine, F1,6BP, and phenylalanine, while Mn, Li, K, NADH, ADP, ATP, citrate, and urea inhibited it. Thermal inactivation studies at 60 °C revealed that the enzyme followed first-order kinetics, with a rate constant of 0.005 min. It effectively hydrolysed raw corn and wheat starch (36.7 % and 39.2 % respectively). Hydrolysis products were identified using thin-layer chromatography. The α-amylase also showed potential for industrial use in apple juice clarification and detergent formulations. The enzyme functioned independently of divalent cations but responded variably to different effectors, suggesting potential for industrial starch processing applications.
本研究报道了从野燕麦种子中生产、纯化和鉴定一种热稳定的、可水解生淀粉的α-淀粉酶。通过一系列步骤,包括pH调节、冻干、聚乙二醇沉淀和多种色谱技术,该酶的纯度提高了16.5倍,最终比活性达到90 U/mg。SDS-PAGE分析证实了该酶的纯度和单体结构,其分子量约为29 kDa。该酶在4℃下表现出高稳定性,半衰期为90天,对乙酰氨基酚可将其延长至121天。动力学值包括K为0.5 mM,V为119 μmol/min/mg蛋白质,kcat为335 s⁻¹。Co、Ca、Mg、Ni、NH₄⁺、NAD、甘氨酸、F1,6BP和苯丙氨酸可增强其活性,而Mn、Li、K⁺、NADH、ADP、ATP、柠檬酸盐和尿素则抑制其活性。60℃下的热失活研究表明,该酶遵循一级动力学,速率常数为0.005 min⁻¹。它能有效水解生玉米淀粉和小麦淀粉(分别为36.7%和39.2%)。使用薄层色谱法鉴定水解产物。该α-淀粉酶在苹果汁澄清和洗涤剂配方中也显示出工业应用潜力。该酶的功能独立于二价阳离子,但对不同效应物的反应各不相同,这表明其在工业淀粉加工应用中有潜力。