L-alpha-Glycerophosphate and L-Lactate Electrodes Based on the Electrochemical Wiring of Oxidases
Technical rept. Oct 1991-Mar 1992
TEXAS UNIV AT AUSTIN DEPT OF CHEMICAL ENGINEERING
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The title electrodes were constructed by co-immobilizing the respective FAD oxidases on solid electrode surfaces with a polyvinyl pyridine polymer which was N-derivatized with bromo ethylamines and Osbpy2C12. The redox-polymer - enzyme hydrogels were crosslinked on the electrode surface using polyethylene glycol diglycidyl ether. As in the case of glucose oxidase, the redox polymer acts as an electron relaying wire transferring electrons directly from the enzymes FADH2 centers to the electrode. This transfer competes with the natural process of reoxidation of the FADH2 by molecular oxygen. The variation of the response of these electrodes with the atmosphere N2 or air, pH, and substrate concentration was determined. The pH profile of the electrocatalytic current differs from that of the activity of the free enzymes, exhibiting a broader maximum, shifted to higher pH values. The observed sensitivities and linear ranges are respectively 2X1O-2 A M-1 cm-2 and 2.7 mM for L-a- glycerophosphate, and 0.3 A M-1 cm-2 and 0.2 mM for I-lactate that may be compared to 2X10-2 A M-1 cm-2 and 10 mM for glucose. The 0-90 response time for all electrodes is 1 sec or less. Electrodes, Electrochemistry, Oxidases, Enzymes.
- Physical Chemistry
- Polymer Chemistry