Glucose oxidase -catalyzed oxidation

Fig. 8.4 (a) In the presence of oxygen, the glucose oxidase-catalyzed oxidation of y -D-glucose leads to the formation of gluconolactone. (b) Carboxypeptidase A selectively cleaves the substrate, hippuryl-L-phenylalanine, thus leading to the formation of hippuric acid and phenylalanine. 

Enantioselective sulfoxidations were performed with the peroxidase from Cop-rinus cinereus (CiPx) by employing glucose oxidase-catalyzed oxidation of glucose for the in situ generation of hydrogen peroxide in [BMIm][PF6]/buffer (90 10,... 

Figure 16.4 Schematic illustration of the implantable glucose monitor under development at Synthetic Blood International. The biosensing mechanism is based on the glucose oxidase-catalyzed oxidation of glucose drawn from tissue fluids. After the enzymatic metabolism, the ratio of hydrogen peroxide to oxygen is detected and expressed by a change in electric current. This signal is transmitted to the receiver outside the body...

Enzymatic reactions may also be followed manometrically (evolution or uptake of a gas), polarimetrically, potentiometrically, fluorimetrically, and by use of ion selective electrodes. The glucose oxidase-catalyzed oxidation of glucose (Equation 10) ... 

Fig. 8.5 The pyranose oxidase-catalyzed oxidation of y -D-glucose leads to the formation of glucosone. Educt and product differ by 2 Da.

The reaction catalyzed by glucose oxidase is oxidation by O2 of the anomeric carbon of (3-D-glucose to a carboxyl group. 

The enzyme glucose oxidase catalyzes the oxidation of glucose to gluconic acid and hydrogen peroxide (H2O2) ... 

Enzyme-mediated feedback can be used to image enzyme patterns. To successfully image enzymatic features, lip fouling from oxide formation or adsorption from solution constituents must be avoided. The enzyme reaction at the substrate must not be inhibited by solution species. It must also be able to sustain a level of regeneration activity of the mediator that can compete with its mass transport from the bulk electrode to the tip. In the case of a glucose oxidase catalyzed reaction, a digital simulation of the positive feedback observed from this enzyme quantitatively expresses this limitation (143). 

The direct incomplete oxidation of sugars without phosphorylation leads to the formation of the corresponding ketones. The aldoses are oxidized into aldonic acids. The aldehydic function of this sugar is transformed into a carboxylic acid function. Glucose is oxidized into gluconic acid in this manner. The glucose oxidase catalyzes the reaction, which is coupled with the reduction of FAD. In acetic acid bacteria, electrons and protons are transported by the cytochrome chain to oxygen, which is the final acceptor. 

A proficient combination of responsiveness and enzjnne immobilization can lead to new sensitive materials. An illustrative example is provided by glucose-responsive polymer systems. Immobilization of glucose oxidase, catalase, and insulin into a pH-responsive polymer gel based on PDMAEMA led to glucose-responsive polymer systems. In the presence of glucose these small sugar molecules diffuse into the polymer gel. Srrbsequently, glucose oxidase catalyzes the oxidation of... 

A bi-enzymatic system (glucose oxidase -I- HRP) was also used to catalyze the synthesis of phenolic polymers. The polymerization of phenol, albeit in moderate yield, was accomplished in the presence of glucose avoiding the addition of hydrogen peroxide (Scheme 2 ), which was formed in situ by the oxidation of glucose catalyzed by glucose oxidase. 

CL reaction can be catalyzed by enzymes other than HRP (e.g., microperoxidase and catalase) and by other substances [hemoglobin, cytochrome c, Fe(III), and other metal complexes]. The presence of suitable molecules such as phenols (p-iodophenol), naphthols (l-bromo-2-naphthol), or amines (p-anisidine) increases the light production deriving from the HRP-catalyzed oxidation of luminol and produces glow-type kinetics [6, 7], The use of other enzymes, such as glucose-6-phosphate dehydrogenase [38-41], P-galactosidase [42], and xanthine oxidase [43-46], as CL labels has been reported. 

---