Wang Yamei, Tian Yixiong, Ban Xiaofeng, Li Caiming, Hong Yan, Cheng Li, Gu Zhengbiao, Li Zhaofeng
School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
Key Laboratory of Synergetic and Biological Colloids, Ministry of Education, Wuxi 214122, China.
Foods. 2022 May 16;11(10):1442. doi: 10.3390/foods11101442.
Amylo-α-1,6-glucosidase (EC 3.2.1.33, AMY) exhibits hydrolytic activity towards α-1,6-glycosidic bonds of branched substrates. The debranching products of maltodextrin, waxy corn starch and cassava starch treated with AMY, pullulanase (EC 3.2.1.41, PUL) and isoamylase (EC 3.2.1.68, ISO), were investigated and their differences in substrate selectivity and debranching efficiency were compared. AMY had a preference for the branched structure with medium-length chains, and the optimal debranching length was DP 13-24. Its optimum debranching length was shorter than ISO (DP 25-36). In addition, the debranching rate of maltodextrin treated by AMY for 6 h was 80%, which was 20% higher than that of ISO. AMY could decompose most of the polymerized amylopectin in maltodextrin into short amylose and oligosaccharides, while it could only decompose the polymerized amylopectin in starch into branched glucan chains and long amylose. Furthermore, the successive use of AMY and β-amylase increased the hydrolysis rate of maltodextrin from 68% to 86%. Therefore, AMY with high substrate selectivity and a high catalytic capacity could be used synergistically with other enzyme preparations to improve substrate utilization and reduce reaction time. Importantly, the development of a novel AMY provides an effective choice to meet different production requirements.
淀粉α-1,6-葡萄糖苷酶（EC 3.2.1.33，AMY）对支链底物的α-1,6-糖苷键具有水解活性。研究了用AMY、普鲁兰酶（EC 3.2.1.41，PUL）和异淀粉酶（EC 3.2.1.68，ISO）处理的麦芽糊精、糯玉米淀粉和木薯淀粉的脱支产物，并比较了它们在底物选择性和脱支效率上的差异。AMY偏好具有中等长度链的支链结构，最佳脱支长度为DP 13 - 24。其最佳脱支长度比ISO（DP 25 - 36）短。此外，AMY处理麦芽糊精6小时的脱支率为80%，比ISO高20%。AMY可将麦芽糊精中大部分聚合的支链淀粉分解为短直链淀粉和寡糖，而它只能将淀粉中的聚合支链淀粉分解为支链葡聚糖链和长直链淀粉。此外，连续使用AMY和β-淀粉酶可使麦芽糊精的水解率从68%提高到86%。因此，具有高底物选择性和高催化能力的AMY可与其他酶制剂协同使用，以提高底物利用率并缩短反应时间。重要的是，新型AMY的开发为满足不同生产需求提供了一种有效选择。
