Jilin Province Key Laboratory on Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China.
Molecules. 2019 Apr 10;24(7):1413. doi: 10.3390/molecules24071413.
Isomaltose-oligosaccharides (IMOs), as food ingredients with prebiotic functionality, can be prepared via enzymatic synthesis using α-glucosidase. In the present study, the α-glucosidase (GSJ) from sp. strain HTA-462 was cloned and expressed in BL21 (DE3). Recombinant GSJ was purified and biochemically characterized. The optimum temperature condition of the recombinant enzyme was 65 °C, and the half-life was 84 h at 60 °C, whereas the enzyme was active over the range of pH 6.0-10.0 with maximal activity at pH 7.0. The α-glucosidase activity in shake flasks reached 107.9 U/mL and using 4-Nitrophenyl β-D-glucopyranoside (NPG) as substrate, the and values were 2.321 mM and 306.3 U/mg, respectively. The divalent ions Mn and Ca could improve GSJ activity by 32.1% and 13.8%. Moreover, the hydrolysis ability of recombinant α-glucosidase was almost the same as that of the commercial α-glucosidase (). In terms of the transglycosylation reaction, with 30% maltose syrup under the condition of 60 °C and pH 7.0, IMOs were synthesized with a conversion rate of 37%. These studies lay the basis for the industrial application of recombinant α-glucosidase.
异麦芽低聚糖（IMO）作为具有益生元功能的食品成分，可以通过使用α-葡萄糖苷酶的酶合成法制备。在本研究中，从 sp. 菌株 HTA-462 克隆并表达了 α-葡萄糖苷酶（GSJ）。重组 GSJ 经纯化并进行了生化特性分析。该重组酶的最适温度条件为 65°C，半衰期为 60°C 时的 84 小时，而该酶在 pH6.0-10.0 范围内具有活性，最大活性在 pH7.0 时。摇瓶中的α-葡萄糖苷酶活性达到 107.9 U/mL，使用 4-硝基苯-β-D-吡喃葡萄糖苷（NPG）作为底物时， 和 值分别为 2.321 mM 和 306.3 U/mg。二价离子 Mn 和 Ca 可以将 GSJ 活性分别提高 32.1%和 13.8%。此外，重组 α-葡萄糖苷酶的水解能力几乎与商业 α-葡萄糖苷酶（）相同。在转糖苷反应中，在 60°C 和 pH7.0 条件下，用 30%的麦芽糖浆，IMO 的转化率为 37%。这些研究为重组 α-葡萄糖苷酶的工业应用奠定了基础。
