%0 Journal Article %1 citeulike:498861 %A Degani, Y. %A Heller, Adam %D 1987 %J The Journal of Physical Chemistry %K electrochemistry gox ferrocene %N 6 %P 1285--1289 %R 10.1021/j100290a001 %T Direct electrical communication between chemically modified enzymes and metal electrodes. I. Electron transfer from glucose oxidase to metal electrodes via electron relays, bound covalently to the enzyme %U http://dx.doi.org/10.1021/j100290a001 %V 91 %X Glucose-reduced glucose oxidase does not directly transfer electrons to conventional electrodes because the distance between its redox centers and the electrode surface exceeds, even on closest approach, the distance across which electrons are transferred at sufficient rates. Therefore, electrical communication between the redox centers of this enzyme and electrodes required either the presence, and diffusion to and from the enzyme’s redox center, of 0, and H202, or the presence of members of a redox couple, or the use of special electrodes like TTFITCNQ. We show here that direct electrical communication between the redox center of a large enzyme molecule and a simple metal electrode can be established through chemical modification of the enzyme. When a sufficient number of electron-relaying centers are attached through covalent bonding to the protein of glucose oxidase, electrons are transferred from the enzyme’s redox centers to relays that are closer to the periphery of the enzyme. Because some of the relays are located sufficiently close to the enzyme’s surface, electrons are transferred at practical rates to the electrode. As a result, a glucose-concentration-dependent current flows in an electrochemical cell made with conventional electrodes when the electrolytic solution contains the relay-modified enzyme. Such a current does not flow when the solution contains the natural enzyme. Specifically, electrical communication is established between the FADIFADH, centers of glucose oxidase and gold, platinum, or carbon electrodes through the covalent bonding of an average of 12 molecules of ferrocenecarboxylic acid per glucose oxidase molecule. The electron-relaying centers are amides of ferrocenecarboxylic acid and primary protein amines. Over 50% of the catalytic activity of the enzyme is retained after the centers for electron transfer are introduced. In pH 7.2 solutions containing the chemically modified enzyme, glucose is electrochemically oxidized at potentials that are more oxidizing than +0.44 Y (SHE).

@article{citeulike:498861, abstract = {Glucose-reduced glucose oxidase does not directly transfer electrons to conventional electrodes because the distance between its redox centers and the electrode surface exceeds, even on closest approach, the distance across which electrons are transferred at sufficient rates. Therefore, electrical communication between the redox centers of this enzyme and electrodes required either the presence, and diffusion to and from the enzyme’s redox center, of 0, and H202, or the presence of members of a redox couple, or the use of special electrodes like TTFITCNQ. We show here that direct electrical communication between the redox center of a large enzyme molecule and a simple metal electrode can be established through chemical modification of the enzyme. When a sufficient number of electron-relaying centers are attached through covalent bonding to the protein of glucose oxidase, electrons are transferred from the enzyme’s redox centers to relays that are closer to the periphery of the enzyme. Because some of the relays are located sufficiently close to the enzyme’s surface, electrons are transferred at practical rates to the electrode. As a result, a glucose-concentration-dependent current flows in an electrochemical cell made with conventional electrodes when the electrolytic solution contains the relay-modified enzyme. Such a current does not flow when the solution contains the natural enzyme. Specifically, electrical communication is established between the FADIFADH, centers of glucose oxidase and gold, platinum, or carbon electrodes through the covalent bonding of an average of 12 molecules of ferrocenecarboxylic acid per glucose oxidase molecule. The electron-relaying centers are amides of ferrocenecarboxylic acid and primary protein amines. Over 50% of the catalytic activity of the enzyme is retained after the centers for electron transfer are introduced. In pH 7.2 solutions containing the chemically modified enzyme, glucose is electrochemically oxidized at potentials that are more oxidizing than +0.44 Y (SHE).}, added-at = {2006-07-07T01:10:50.000+0200}, author = {Degani, Y. and Heller, Adam}, biburl = {https://www.bibsonomy.org/bibtex/2dfbfba0a8c3cdd09a1335a8f99f59b97/biblio24}, citeulike-article-id = {498861}, doi = {10.1021/j100290a001}, interhash = {a103f3a0ead9cd8a09d169e279c2c5c8}, intrahash = {dfbfba0a8c3cdd09a1335a8f99f59b97}, journal = {The Journal of Physical Chemistry}, keywords = {electrochemistry gox ferrocene}, month = {March}, number = 6, pages = {1285--1289}, priority = {2}, timestamp = {2006-07-07T01:10:50.000+0200}, title = {Direct electrical communication between chemically modified enzymes and metal electrodes. I. Electron transfer from glucose oxidase to metal electrodes via electron relays, bound covalently to the enzyme}, url = {http://dx.doi.org/10.1021/j100290a001}, volume = 91, year = 1987 }