Improving the Environment for Immobilized Dehydrogenase Enzymes by Modifying Nafion with Tetraalkylammonium Bromides

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• 作者：Christine M. Moore ; Nick L. Akers ; Adam D. Hill ; Zachary C. Johnson ; and Shelley D. Minteer
• 刊名：Biomacromolecules
• 出版年：2004
• 出版时间：July 2004
• 年：2004
• 卷：5
• 期：4
• 页码：1241 - 1247
• 全文大小：429K
• 年卷期：v.5,no.4(July 2004)
• ISSN：1526-4602

文摘

Recent research in our group has shown that mixture-casting Nafion with quaternary ammonium bromidescan increase the electrochemical flux of redox couples through the membrane and allow for larger redoxspecies to diffuse to the electrode surface. The research has also suggested that when these salts are castwith Nafion micellar pore size is changing. Therefore, it was proposed that the quaternary ammonium saltscould be employed to tailor the structure of the Nafion membrane for immobilizing enzymes in the polymer.For cations with a high affinity for the sulfonic acid groups of Nafion, the modified structure of Nafion canalso help to stabilize the enzyme and increase activity by providing a protective outer shell and an idealchemical environment that resists a decrease in pH within the pore structure. This research examines theability to immobilize dehydrogenase enzymes in Nafion that has been modified with quaternary ammoniumbromides. Fluorescence assays, fluorescence microscopy, and cyclic voltammetric studies were employedto analyze the ability to immobilize an enzyme within the membrane, to determine the activity of theimmobilized enzyme and to examine the transport of coenzyme within the membrane. Dehydrogenase enzymesimmobilized in tetrabutylammonium bromide/Nafion membranes have shown high catalytic activity andenzyme active lifetimes of greater than 45 days. A variety of dehydrogenase enzymes have been successfullyimmobilized in the membrane, including: alcohol dehydrogenase, aldehyde dehydrogenase, glucosedehydrogenase, and lactic dehydrogenase.