College of Life Sciences of Liaocheng University, Liaocheng, 252000, People's Republic of China.
Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences of Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
Appl Biochem Biotechnol. 2024 Sep;196(9):6492-6507. doi: 10.1007/s12010-024-04874-x. Epub 2024 Feb 22.
A novel amylase AmyFlA from Flavobacterium sp. NAU1659, AmyFlA, was cloned and expressed in Esherichia coli. Based on phylogenetic and functional analysis, it was identified as a novel member of the subfamily GH13_46, sharing high sequence identity. The protein was predicted to consist of 620 amino acids, with a putative signal peptide of 25 amino acids. The enzyme was able to hydrolyze soluble starch with a specific activity of 352.97 U/mg at 50 °C in 50 mM phosphate buffer (pH 6.0). The K and V values of AmyFlA were respectively 3.15 mg/ml and 566.36 µmol·ml·min under optimal conditions. Its activity towards starch was enhanced by 63% in the presence of 1 mM Ca, indicating that AmyFlA was a Ca-dependent amylase. Compared to the reported maltogenic amylases, AmyFlA produced a lower variety of intermediate oligosaccharides at the start of the reaction so that the product mixture contained a higher proportion of maltose. These results indicate that AmyFlA may be potential application value in the production of high-maltose syrup.
从黄杆菌 NAU1659 中克隆并在大肠杆菌中表达了一种新型淀粉酶 AmyFlA。基于系统发育和功能分析,它被鉴定为 GH13_46 亚家族的一个新型成员,具有很高的序列同一性。该蛋白预测由 620 个氨基酸组成,具有 25 个氨基酸的假定信号肽。该酶能够在 50°C、50mM 磷酸盐缓冲液(pH 6.0)中以 352.97 U/mg 的比活性水解可溶性淀粉。在最佳条件下,AmyFlA 的 K 和 V 值分别为 3.15mg/ml 和 566.36µmol·ml·min。在 1mM Ca 的存在下,其对淀粉的活性提高了 63%,表明 AmyFlA 是一种依赖 Ca 的淀粉酶。与报道的麦芽寡糖淀粉酶相比,AmyFlA 在反应开始时产生的中间低聚糖种类较少,因此产物混合物中含有较高比例的麦芽糖。这些结果表明,AmyFlA 在生产高麦芽糖糖浆方面可能具有潜在的应用价值。
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