正反胶束体系中木素过氧化物催化氧化藜芦醇条件优化

Optimization on the conditions of Lip-catalyzed oxidation veratryl alcohol in the micellar and reverse micellar systems

对比研究了单鼠李糖脂(RL)构建的反胶束和胶束体系中木素过氧化物酶(Lip)催化氧化藜芦醇(VA)的各主要影响因素,同时探讨了疏水性底物VA在非均相反胶束介质中的分区系数.结果表明:在30℃下,在RL/异辛烷-正己醇(V:V,1:1)/水反胶束体系中,Lip能保持较高活性的最佳介质条件是:pH=3.8,[RL]=10mmol/L,w0=15.0,[H2O2]=74μmol/L,这不同于RL胶束介质中的最佳催化条件:pH=3.4,[RL]=0.012mmol/L,[H2O2]=2.45mmol/L.在最佳催化条件下,Lip的半衰期达40h,催化活力是胶束水相中的2.86倍.根据两相模型及相应的动力学方法计算得出VA主要增溶于反胶束拟相中,其在反胶束拟相和有机相间的分区系数为70.4.分区系数的确定对于进一步讨论RL反胶束体系中Lip催化氧化VA的动力学机制而言具有重要意义.

The main factors which affected the catalytic oxidation of veratryl alcohol （VA） by lignin peroxidase（Lip） entrapped in rhamnolipid（RL） reverse micellar or micellar systems were investigated. Meanwhile, the partition coefficient of insoluble substrate VA in the heterogeneous reverse micellar medium were studied. It was shown that Lip hosted in RL/isooctane-n-hexanol（l：l,V：IO/water reverse micellar system could express higher enzymatic activity under the following conditions： pH 3.8, [RL]=10mmol/L, w0=l 5.0, [H2OE]=74~raoFL. With respect to the RL micellar system, the optimum values were as follows： pH 3.4, [RL]=0.012mmol/L, [H202]=2.45mmol/L. In optimum catalytic conditions, the half-life of Lip was 40h, and the catalytic activity in reverse micelle was 2.86 times than that in micellar system. Based on the biphasic model and the corresponding kinetic method, a conclusion could be made that VA was mainly solubilized in the pseudophase of reverse micelle, and the partition coefficient of VA between the pseudophase and organic solvent phase was 70.4. The determination of partition coefficient is important for further discussing the kinetic mechanism of Lip-catalyed oxidation VA in the RL reverse micellar system.