College of Food Science and Engineering , Ocean University of China , Qingdao 266003 , China.
Laboratory for Marine Drugs and Bioproducts , Qingdao National Laboratory for Marine Science and Technology , Qingdao 266237 , China.
J Agric Food Chem. 2019 Sep 18;67(37):10373-10379. doi: 10.1021/acs.jafc.9b03073. Epub 2019 Sep 5.
Agarose can be hydrolyzed into agarooligosaccharides (AOSs) by α-agarase, which is an important enzyme for efficient saccharification of agarose or preparation of bioactive oligosaccharides from agarose. Although many β-agarases have been reported and characterized, there are only a few studies on α-agarases. Here, we cloned a novel α-agarase named CaLJ96 with a molecular weight of approximately 200 kDa belonging to glycoside hydrolase family 96 from . CaLJ96 has good pH stability and exhibits maximum activity at 37 °C and pH 7.0. The hydrolyzed products of agarose by CaLJ96 are analyzed as agarobiose (A2), agarotetraose (A4), and agarohexaose (A6), in which A4 is the dominant product. CaLJ96 can hydrolyze agaropentaose (A5) into A2 and agarotriose (A3) and A6 into A2 and A4 but cannot act on A2, A3, or A4. This is the first report to characterize the α-agarase action on AOSs in detail. Therefore, CaLJ96 has potential for the manufacture of bioactive AOSs.
琼胶可以被α-琼胶酶水解成琼寡糖（AOSs），α-琼胶酶是一种高效水解琼胶或从琼胶制备生物活性寡糖的重要酶。尽管已经报道和表征了许多β-琼胶酶，但对α-琼胶酶的研究却很少。在这里，我们从 中克隆了一种新型的α-琼胶酶 CaLJ96，分子量约为 200 kDa，属于糖苷水解酶家族 96。CaLJ96 具有良好的 pH 稳定性，在 37°C 和 pH 7.0 时表现出最大活性。琼脂糖的水解产物用 CaLJ96 分析为琼脂二糖（A2）、琼脂四糖（A4）和琼脂六糖（A6），其中 A4 是主要产物。CaLJ96 可以将琼脂五糖（A5）水解成 A2 和琼脂三糖（A3）和 A6 成 A2 和 A4，但不能作用于 A2、A3 或 A4。这是首次详细报道 α-琼胶酶对 AOSs 的作用。因此，CaLJ96 具有制造生物活性 AOSs 的潜力。
