Biocatalysis in Water-in-Ionic Liquid Microemulsions: A Case Study with Horseradish Peroxidase
Biocatalysis in Water-in-Ionic Liquid Microemulsions: A Case Study with Horseradish Peroxidase
复制标题
DOI：
10.1021/la803118q
复制
发表时间：
2009-01-20
期刊：
影响因子：
3.9
通讯作者：
Goto, A.
中科院分区：
文献类型：
--
作者：
Moniruzzaman, M.;Kamiya, N.;Goto, A.
本文首次报道了以邻苯三酚为底物的离子液体(W/IL)微乳液中辣根过氧化物酶(HRP)的酶活性。为了达到这一目标，本研究中使用的体系由阴离子表面活性剂Aot(Na bis(2-ethyl-1-hexyl)sulfosuccinate)/hydrophobic IL[C(8)MIM][Tf2N](1-辛基-3-甲基咪唑bis(trifluoromethylsulfonyl)amide)/water/1-hexanol.)组成在该体系中，测定了HRP的催化活性与底物浓度、W-0(水与表面活性剂的摩尔比)、pH和1-己醇含量的函数关系。新型微乳液的活性-W-0曲线为双曲线。估算了表观Michaelis-Menten动力学参数(k(Cat)和K-m)，并与常规微乳液的结果进行了比较。显然，在IL微乳中，HRP催化过氧化氢氧化邻苯三酚比在AOT/水/异辛烷微乳中更有效。考察了新开发的W/IL微乳中HRP的稳定性，发现在28℃下孵育30h后，HRP的活性几乎保持了初始活性的70%。
In this article we report die first results on the enzymatic activity of horseradish peroxidase (HRP) microencapsulated in water-in-ionic liquid (w/IL) microemulsions using pyrogallol as the substrate. Toward this goal, the system used in this study was composed of anionic surfactant AOT (sodium bis(2-ethyl-1-hexyl)sulfosuccinate)/hydrophobic IL [C(8)mim][Tf2N] (1-octyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)amide)/water/1-hexanol. In this system, the catalytic activity of HRP was measured as a function of substrate concentrations, W-0 (molar ratio of water to surfactant), pH, and 1-hexanol content. The curve of the activity-W-0 profile was found to be hyperbolic for the new microemulsion. The apparent Michaelis-Menten kinetic parameters (k(cat) and K-m) were estimated and compared to those obtained from a conventional microemulsion. Apparently, it-was found that HRP-catalyzed oxidation of pyrogallol by hydrogen peroxide in IL microemulsions is much more effective than in a conventional AOT/water/isooctane microemulsion. The stability of HRP solubilized in the newly developed W/IL microemulsions was examined, and it was found that HRP retained almost 70% of its initial activity after incubation at 28 degrees C for 30 h.