Klis Maciej, Karbarz Marcin, Stojek Zbigniew, Rogalski Jerzy, Bilewicz Renata
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
J Phys Chem B. 2009 Apr 30;113(17):6062-7. doi: 10.1021/jp8094159.
We report on the properties of hydrogel matrix for the immobilization of laccase on conductive supports. The poly(N-isopropylacrylamide) gel is attached firmly to the indium-tin oxide (ITO) electrode, following its silanization with dimethylethoxyvinylsilane. The enzyme entrapped in the gel structure remained active longer than in the solution, and its redox and catalytic properties could be investigated by voltammetric methods. The reduction signals of the active sites, T1 and T2, of the Cerrena unicolor laccase were determined to be 0.79 and 0.38 V, respectively. The laccase catalytic activity toward oxygen in poly(N-isopropylacrylamide) was found to depend strongly on temperature. Reversible swelling/shrinking of the matrix was studied at 30 and 35 degrees C. Shrinking of the gel at higher temperature considerably decreased the efficiency of the catalytic reaction, however, interestingly, did not lead to irreversible changes in the enzyme structure. At temperatures below that corresponding to volume phase transition, the catalytic properties of the film were fully restored. High catalytic efficiency of the gel immobilized enzyme made it possible to employ the gel covered electrode for monitoring oxygen in solutions.
我们报道了用于将漆酶固定在导电载体上的水凝胶基质的性质。聚（N-异丙基丙烯酰胺）凝胶在用二甲基乙氧基乙烯基硅烷进行硅烷化处理后，牢固地附着在氧化铟锡（ITO）电极上。包埋在凝胶结构中的酶比在溶液中保持活性的时间更长，并且可以通过伏安法研究其氧化还原和催化性质。单色蜡蘑漆酶活性位点T1和T2的还原信号分别测定为0.79 V和0.38 V。发现聚（N-异丙基丙烯酰胺）中漆酶对氧气的催化活性强烈依赖于温度。在30和35摄氏度下研究了基质的可逆溶胀/收缩。在较高温度下凝胶的收缩大大降低了催化反应的效率，然而，有趣的是，并没有导致酶结构的不可逆变化。在低于体积相变对应的温度下，膜的催化性质完全恢复。凝胶固定化酶的高催化效率使得可以使用凝胶覆盖电极来监测溶液中的氧气。
