College of Food Science and Engineering, Shanxi Agricultural University, Taigu 030801, China; Collaborative Innovation Center of Advancing Quality and Efficiency of Loess Plateau Edible Fungi, Taigu, 030801, China.
College of Food Science and Engineering, Shanxi Agricultural University, Taigu 030801, China; Collaborative Innovation Center of Advancing Quality and Efficiency of Loess Plateau Edible Fungi, Taigu, 030801, China.
Int J Biol Macromol. 2018 Dec;120(Pt B):2165-2174. doi: 10.1016/j.ijbiomac.2018.09.021. Epub 2018 Sep 5.
A novel 57-kDa acidic α-galactosidase designated as HEG has been purified from the dry fruiting bodies of Hericium erinaceus. The isolation protocol involved ion-exchange chromatography and gel filtration on a Superdex75 column. The purification fold and specific activity were 1251 and 46 units/mg, respectively. A BLAST search of internal peptide sequences obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis suggested that the enzyme belonged to the GH27 family. The activity of the enzyme reached its maximum at a pH of 6.0 or at 60 °C. The enzyme was stable within an acidic pH range of 2.2-7.0 and in a narrow temperature range. The enzyme was strongly inhibited by Zn, Fe, Ag ions and SDS. The Lineweaver-Burk plot suggested that the mode of inhibition by galactose and melibiose were of a mixed type. N-bromosuccinimide drastically decreased the activity of the enzyme, whereas diethylpyrocarbonate and carbodiimide strengthened the activity slightly. Moreover, the isolated enzyme displayed remarkable resistance to acid proteases, neutral proteases and pepsin. The enzyme could also hydrolyse oligosaccharides and polysaccharides. In addition, acidic protease promoted the hydrolysis of RFOs by HEG. The K values of the enzyme towards pNPGal, raffinose and stachyose were 0.36 mM, 40.07 mM and 54.71 mM, respectively. These favourable properties increase the potential of the enzyme in the food industry and animal feed applications.
从猴头菇（Hericium erinaceus）的干燥子实体中分离到一种新型 57 kDa 酸性α-半乳糖苷酶，命名为 HEG。该分离方案涉及离子交换层析和 Superdex75 柱凝胶过滤。纯化倍数和比活分别为 1251 和 46 单位/毫克。通过液相色谱-串联质谱（LC-MS/MS）分析获得的内部肽序列的 BLAST 搜索表明，该酶属于 GH27 家族。该酶的活性在 pH6.0 或 60°C 时达到最大值。该酶在 2.2-7.0 的酸性 pH 范围内和较窄的温度范围内稳定。该酶强烈抑制 Zn、Fe、Ag 离子和 SDS。Lineweaver-Burk 作图表明，半乳糖和棉子糖的抑制模式为混合类型。N-溴代丁二酰亚胺大大降低了酶的活性，而二乙基焦碳酸酯和碳二亚胺则略微增强了酶的活性。此外，分离得到的酶对酸性蛋白酶、中性蛋白酶和胃蛋白酶具有很强的抗性。该酶还可以水解低聚糖和多糖。此外，酸性蛋白酶可促进 HEG 水解 RFOs。该酶对 pNPGal、棉子糖和水苏糖的 K 值分别为 0.36mM、40.07mM 和 54.71mM。这些有利的特性增加了该酶在食品工业和动物饲料应用中的潜力。
