木霉LE02 β-1，3-葡聚糖酶酶学特性的研究

Enzymatic Properties of β-1,3-Glucanase from Trichoderma Strain LE02

对木霉菌株LE02所产β-1,3-葡聚糖酶的酶学特性进行了研究。结果表明,该酶最适反应温度为55℃、最适反应pH值为5.0。Co^(2+)、K+、Zn^(2+)、Li^+、Ba^(2+)、Cu^(2+)以及1.0mmol/L的Fe^(2+)对该酶没有影响,Cd^(2+)和10.0mmol/L的Mg^(2+)对酶具有部分抑制作用,而低浓度的Hg^(2+)、5.0mmol/L以上的Mn^(2+)和10.0 mmol/L的Fe^(3+)能强烈抑制该酶的活性。该酶只能作用于β-1,3-糖苷键,以Larinami为底物时其米氏常数K_m值为128.34μg/mL,最大反应速度V_m为23.01μg/(min·mL)。经过SDS-PAGE测定的分子质量近似为80.137ku。

Enzymatic properties of β-1, 3-glucanase derived from Trichoderma strain LE02 were investigated. The optimum reaction temperature and pH of the enzyme were 55℃ and 5.0, respectively. The enzyme activity was stable below 50℃ and between pH 4.5 and pH 6.0. The enzyme activity was not inhibited by Co^2＋ , K^＋ , Zn^2＋ , Li^＋ , Ba^2＋ , Cu^2＋ and 1. 0 mmol/L Fe^2＋ , but was slightly inhibited by Cd^2＋ and 10.0 mmol/L Mg^2＋ , and was strongly inhibited by Hg^2＋ , Mn^2＋ over 5.0 mmol/L and 10.0 mmol/L Fe^3＋. The enzyme only catalyzed the hydrolysis of β-1, 3-glucosidic linkages. The Km values and Vmax of β-1, 3-glucanase were 128. 34 μg/mL and 23.0l μg/min·mL with the substrate of laminarin. The molecular weight estimated bv SDS-PAGE was about 80. 137 ku.