College of Basic Medicine, Qingdao University, Qingdao 266071, China.
Mar Drugs. 2020 Feb 19;18(2):126. doi: 10.3390/md18020126.
Chitooligosaccharide (COS) has been recognized to exhibit efficient anti-oxidant activity. Enzymatic hydrolysis using chitosanases can retain all the amino and hydroxyl groups of chitosan, which are necessary for its activity. In this study, a new chitosanase encoding gene, , was cloned from the marine sp. Q1098 and expressed in . The recombinant chitosanase, CsnQ, showed maximal activity at pH 5.31 and 60 °C. Determination of CsnQ pH-stability showed that CsnQ could retain more than 50% of its activity over a wide pH, from 3.60 to 9.80. CsnQ is an endo-type chitosanase, yielding chitodisaccharide as the main product. Additionally, in vitro and in vivo analyses indicated that chitodisaccharide possesses much more effective anti-oxidant activity than glucosamine and low molecular weight chitosan (LMW-CS) (~5 kDa). Notably, to our knowledge, this is the first evidence that chitodisaccharide is the minimal COS fragment required for free radical scavenging.
壳寡糖（COS）已被证实具有高效的抗氧化活性。壳聚糖酶的酶解可以保留壳聚糖所有的氨基和羟基，这些基团是其活性所必需的。在这项研究中，从海洋 sp. Q1098 中克隆了一种新的壳聚糖酶编码基因 ，并在 中表达。重组壳聚糖酶 CsnQ 在 pH5.31 和 60°C 时表现出最大活性。CsnQ 的 pH 稳定性测定表明，CsnQ 在 pH3.60 到 9.80 的较宽范围内可以保留超过 50%的活性。CsnQ 是一种内切型壳聚糖酶，主要产物为壳二糖。此外，体外和体内分析表明，壳二糖的抗氧化活性比氨基葡萄糖和低分子量壳聚糖（LMW-CS）（~5 kDa）强得多。值得注意的是，据我们所知，这是壳二糖是用于清除自由基的最小 COS 片段的第一个证据。
