Song Hyun-Kon, Palmore G Tayhas R
Division of Engineering, Brown University, Providence, Rhode Island 02912, USA.
J Phys Chem B. 2005 Oct 20;109(41):19278-87. doi: 10.1021/jp0514978.
Laccase catalyzes the polymerization of pyrrole into a conducting polymer using dioxygen as the terminal oxidant. This finding is significant, because it identifies an enzymatic route, and thus an environmentally benign method, for preparing a technologically important polymer. In addition, the rate of oxidation of pyrrole increases when the redox molecule, ABTS [2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate)], is included in a reaction medium that contains laccase. This increase in rate occurs because laccase catalyzes the oxidation of ABTS to ABTS*. In addition to laccase, the biocatalytically generated ABTS* oxidizes pyrrole to its corresponding radical cation to yield polypyrrole. Moreover, oxidation of pyrrole by ABTS* regenerates ABTS for subsequent biocatalytic turnover. Including ABTS in the reaction medium has two important consequences for the final product: (a) The reaction proceeds rapidly enough to form polymeric films instead of oligomeric precipitates, and (b) ABTS remains within the polymeric film as a redox-active dopant. The charge transport properties of the resulting polymers, both with and without ABTS as the counteranion, are compared to those of other conducting materials including polypyrrole prepared electrochemically or chemically.
漆酶以双氧作为末端氧化剂催化吡咯聚合成导电聚合物。这一发现意义重大，因为它确定了一种制备具有重要技术意义聚合物的酶促途径，也就是一种环境友好型方法。此外，当氧化还原分子2,2'-联氮双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)存在于含有漆酶的反应介质中时，吡咯的氧化速率会增加。速率的增加是因为漆酶催化ABTS氧化为ABTS*。除了漆酶，生物催化产生的ABTS将吡咯氧化为其相应的自由基阳离子以生成聚吡咯。此外，ABTS氧化吡咯会使ABTS再生以进行后续的生物催化周转。在反应介质中加入ABTS对最终产物有两个重要影响：(a)反应进行得足够快以形成聚合物膜而不是低聚物沉淀，(b)ABTS作为氧化还原活性掺杂剂保留在聚合物膜内。将所得聚合物（有无ABTS作为抗衡阴离子）的电荷传输性能与其他导电材料（包括通过电化学或化学方法制备的聚吡咯）的电荷传输性能进行比较。
