摘要
利用PCR从噬琼胶菌AL1中扩增琼胶酶基因,将其克隆至表达载体p ET-28a;表达产物用亲和层析纯化,研究重组酶的酶学性质;利用薄层色谱和质谱鉴定酶解产物,并测定酶解产物的还原能力和清除DPPH、ABTS+和·OH自由基的能力,分析酶解产物的抗氧化活性。结果表明,来自噬琼胶菌AL1重组琼胶酶的分子质量为105 ku。该琼胶酶能专一地降解琼脂,为β-琼胶酶。重组琼胶酶在50℃和p H 7.0表现出最大酶活力,在50℃以下,p H 5.00~11.00宽p H范围内稳定性良好,说明该重组酶具有良好的热稳定性和p H稳定性。经薄层色谱和质谱鉴定酶解产物为新琼二糖,该酶解产物对·OH、ABTS和DPPH自由基的半数抑制剂量IC50分别为1.28 mg/mL、3.46 mg/mL和9.87 mg/mL,还原能力较强,说明该酶解产物具有良好的抗氧化活性。
The agarase gene AL1 was amplified by PCR and cloned into pET-28 a expression vector.The expression product was purified by affinity chromatography to study the enzymatic properties of the recombinant enzyme.The enzymatic hydrolysate was identified by TLC and LC-MS,and its reducing ability and scavenging ability of DPPH,ABTS+·and·OH radicals were determined,and the antioxidant activity of the hydrolysate was analyzed.The molecular weight of the recombinant agarase from Agarivorans sp.AL1 was 105 ku.The agarase could specifically degrade agar as aβ-agarase.The recombinant agarase showed the maximum activity at 50℃and p H 7.00.The recombinant agarase was stable in a wide pH range from 5.00 to 11.00 below 50℃,indicating that the recombinant enzyme had good thermal stability and p H stability.The enzymatic hydrolysate product was identified as neoagarobiose by TLC and LC-MS.The enzymatic hydrolysates had the reducing power.The half-inhibition concentration IC50 of the enzymatic hydrolysate to·OH,ABTS and DPPH free radicals are 1.28 mg/mL,3.46 mg/m L and 9.87 mg/m L,respectively,indicating that the hydrolysate had good antioxidant activity.
作者
刘雪
陈艳红
姜泽东
倪辉
李清彪
朱艳冰
LIU Xue;CHEN Yan-hong;JIANG Ze-dong;NI Hui;LI Qing-biao;ZHU Yan-bing(College of Food and Biological Engineering,Jimei University,Xiamen 361021,China;Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering,Research Center of Food Biotechnology of Xiamen City,Xiamen 361021,China)
出处
《现代食品科技》
CAS
北大核心
2021年第5期82-90,共9页
Modern Food Science and Technology
基金
福建省海洋经济发展补助资金项目(FJHJF-L-2020-1)
漳州市科技重大专项(ZZ2019ZD15)。
关键词
噬琼胶菌
重组琼胶酶
酶学性质
酶解产物
Agarivorans sp.
recombinant agarase
enzymatic properties
enzymatic product