微泡菌ALW1昆布多糖酶的酶学性质及其酶解产物的抗氧化活性

Enzymatic Characterization of Laminarinase from Microbulbifer sp.ALW1 and Antioxidant Activity of Its Hydrolysates

本文研究微泡菌ALW1胞外昆布多糖酶的酶学性质及其酶解产物的抗氧化活性。研究结果显示,以昆布多糖为底物,菌株ALW1胞外昆布多糖酶的最适反应温度为45℃,在35℃下酶活性较稳定;酶的最适反应pH 5.5,在pH 6.0~8.0范围内酶活性较为稳定;Na+对酶活力起促进作用,而K+,Fe^2+,Cu^2+,Co^2+,Mn^2+,Ba^2+,Cd^2+和Zn^2+对昆布多糖酶具有不同程度的抑制作用。昆布多糖酶的酶解产物具有还原能力和清除2'-联氨-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基和·OH自由基的能力,对ABTS自由基和·OH自由基的半抑制剂量IC50分别为15.2 mg/mL和1.7 mg/mL,表明酶解产物有一定的抗氧化能力。

This study aims to study the enzymatic characterization of extracellular laminarases from Microbulbifer sp.ALW1 and the antioxidant activity of the enzymatic hydrolysates.The results showed that the optimum temperature of laminarinase was 45℃using laminarin as the substrate,and the enzyme activity was stable under 35℃.The optimum pH of laminarinase was 5.5,and the enzymatic activity was stable at pH between 6.0 and 8.0.Na+could promote the enzyme activity,but K+,Fe^2+,Cu^2+,Co^2+,Mn^2+,Ba^2+,Cd^2+and Zn^2+could inhibit the laminarinase activity to some extent.The enzymatic hydrolysates had reducing ability and scavenging power on ABTS and hydroxyl radicals.The half inhibitory concentration(IC50)values of scavenging activity towards ABTS and hydroxyl radicals were 15.2 mg/mL and 1.7 mg/mL,respectively.These results showed that the enzymatic hydrolysates had antioxidant activity.