摘要
通过硫酸铵分级沉淀、透析等方法从白芥子中提取、分离和纯化得到芥子酶。结果显示,0~20%硫酸铵饱和度部分提取所得酶液比活力最大,为7.8U/mg。利用葡萄糖试剂盒法和高效液相色谱测定酶活,对芥子酶酶学特性进行研究。结果表明,白芥芥子酶的分子量约为75 kDa,最适pH为7,最适温度为55℃;NaCl溶液对芥子酶活力有抑制作用;Vc能有效地促进酶活,添加0.1 mmol/LVc时的酶活为对照组的4.8倍;酶浓度与酶活并非呈线性正相关关系;常压(0.1 MPa)下的米氏常数Km=1.265 mmol/L,最大反应速度V_(max)=0.150mmol/min。
The myrosinase was extracted and purified from white mustard seeds by ammonium sulfate precipitation and dialysis.The results showed that the most active component was that extracted from 0-20% ammonium sulfate saturation and the activity was 7.8U/mg.Enzyme activity was determined by the method of glucose kits in combination with high performance liquid chromatography(HPLC) to research its enzymatic characteristics.The results showed the optimum pH was 7 and the optimum temperature was 55 ℃;NaCl could inhibit myrosinase activity;Vc could activate enzyme effectively,the enzyme activity in 0.1 mmol/L Vc was 4.8 times higher than that of no Vc added.Enzyme concentration and enzyme activity did not have a linear positive correlation;the K_m and maximum reaction rate V_(max) under the atmospheric pressure(0.1 MPa) were 1.265 mmol/L and 0.150 mmol/min,respectively.
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