Glucose horseradish peroxidase electrode

Bioelectrocatalysis involves the coupling of redox enzymes with electrochemical reactions [44]. Thus, oxidizing enzymes can be incorporated into redox systems applied in bioreactors, biosensors and biofuel cells. While biosensors and enzyme electrodes are not synthetic systems, they are, essentially, biocatalytic in nature (Scheme 3.5) and are therefore worthy of mention here. Oxidases are frequently used as the biological agent in biosensors, in combinations designed to detect specific target molecules. Enzyme electrodes are possibly one of the more common applications of oxidase biocatalysts. Enzymes such as glucose oxidase or cholesterol oxidase can be combined with a peroxidase such as horseradish peroxidase. 

Eshkenazi et al. [46] Lactose Fresh raw milk /3-Galactosidase, glucose oxidase, and horseradish peroxidase/with PEI and glutaraldehyde Glassy carbon electrode/ 0 V vs. SCE 5-Aminosalicylic acid (in solution)... 

Min et al. [17] Glucose L-Lactate Lactococcus lactis (ATCC 19435) fermentation Glucose oxidase (GOx) or L-lactate oxidase (LOx) with horseradish peroxidase (HRP)/in a carbon paste matrix with polyethyleneimine and a polyester sulfonic acid cation exchanger (Eastman AQ-29D) Carbon paste electrode/-50 mV vs. Agf AgCl ... 

The flexibility of the sol-gel process allows multiple approaches to enzymatic activity monitoring. The formation of hydrogen peroxide can be followed by optical measmements using another enzymatic reaction in which the oxidation of an organic dye is catalyzed by a peroxidase (HorseRadish Peroxidase HRP), coentrapped with GOD. The presence of glucose in the solution can also be detected via electrochemical means by following the redox reactions at the active site of GOD. However, because of the steric hindrance of the protein molecule, a ferrocene mediator has to be used in order to transfer electrons from the hidden active site to the electrode. Alternatively, oxygen consumption can be measmed with a Clark electrode. The hybrid gel is deposited on a Pt cathode... 

CCEs have also been used in conjunction with enzymes. Glucose oxidase was encapsulated within the methyl silicate (or silica)-graphite composite [216, 220]. Reduced oxygen from the enzymatic reaction results in the production of H2O2, which is oxidized at the electrode. Palladium and rhodium catalysts have been added to the electrode to help lower the over voltage required for hydrogen peroxide oxidation [219, 221]. Glucose oxidase and horseradish peroxidase have been simultaneously entrapped within a CCE for a biosensor that does not require a... 

Mackey, D., Killard, A.J., and Ambrosi, A. (2007) Optimizing the ratio of horseradish peroxidase and glucose oxidase on a bienzyme electrode comparison of a theoretical and... 

Several authors investigated ion selective electrodes incorporating GOD coupled with oxidative reactions catalyzed by horseradish peroxidase (HRP). Thus, glucose has been determined by measuring iodide concentration at an iodide sensitive electrode (Nagy at al., 1973) according to ... 

Aromatic amines are activators of horseradish peroxidase. Kulys and Vidziunaite (1983) adsorbed HRP together with GOD on a carbon electrode and crosslinked the enzymes with glutaraldehyde to assemble a sensor for aromatic amines. H2O2 is produced in the presence of glucose, acting as cosubstrate in the HRP-catalyzed oxidation of ferrocyanide. The ferricyanide formed was reduced back to ferrocyanide at an electrode potential of +10 mV vs SCE, the current being limited by the... 

FIG. 7 Approach curve of a H202-selective amperometric tip electrode towards a polymer layer loaded with GOx. The tip was produced by immobilizing horseradish peroxidase onto the cross section of an insulated carbon fiber of 7 /xm diameter. Solution composition 1 mM glucose in air-saturated 0.2 M phosphate buffer, pH 7. (From Ref. 22. Copyright 1993 American Chemical Society.)... 

Glucose oxidase, Horseradish peroxidase Silver NP/CNT/Chitosan modified indium tin oxide electrode Glucose biosensor [135]... 

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