Hydrogen peroxide accumulation

Sulfonamides (c)P Or by inhibiting catalase, hydrogen peroxide accumulating... 

An inner-sphere hydrogen atom abstraction from the alcohol by a peroxo metal complex, thus forming a coordinated ketyl radical [(CH3)2—C —O—V(0)(00H)]" , has been proposed for the aerobic oxidation of alcohols catalyzed by peroxidic molybdenum and vanadium derivatives (Scheme 16). While in the case of Mo-catalyzed reaction the H2O2 produced is quantitatively converted to products (ketone and H2O), in the vanadium mediated process, hydrogen peroxide accumulates . In this latter case, the direct involvement of a vanadium monoperoxo species has been substantiated by ESI-MS data. 

Grufferty, R. C. and Condon, S. 1983. Effect of fermentation sugar on hydrogen peroxide accumulation by Streptococcus lactis CIO. J. Dairy Res. 50, 481-489. 

Leoncini, G., and Poggi, M. 1996. Effects of methylglyoxal on platelet hydrogen peroxide accumulation, aggregation and release reaction. Cell Biochem Funct 14 89-95. 

Fig. 27. Construction of a double measuring cell. For the determination of the apparent enzyme activity at the GOD electrode the rate of hydrogen peroxide accumulation in the measuring cell, U2, is indicated by using an enzyme-free electrode polarized to +600 mV. By contrast, when glucose is measured, the H2O2 diffusing to the enzyme sensor is indicated, and during the short time period of the measurement only a negligible amount of H2O2 diffuses into the measuring cell.

Fig. 28. Dependence of the hydrogen peroxide accumulation rate, i>2, on substrate concentration as measured in the double measuring cell depicted in Fig. 27. V2 is a measure of the apparent activity of G OD entrapped in a gelatin membrane. A membrane area of 0.13 mm2 was exposed to the measuring solution. The enzyme layer was sandwiched between two dialysis membranes. Solution 66 mmol/1 phosphate buffer, pH 7.0 25°C GOD loading 1-46 U/cm2, i.e., 6 U per electrode 2-46 mU/cm2, i.e. 6 mU per electrode.

Figure 2. Effect of pH on hydrogen peroxide accumulation. Total HOAc/OAc concentration is 0.015 M.

Figure 3. Hydrogen peroxide accumulation in the presence of acetic and sulfuric acids.

In the case under consideration, the objective is to reveal the influence of individual steps on the kinetics of hydrogen peroxide accumulation. On this basis initial values for the reaction species, y/i (to) 1, for hydrogen peroxide, and 0, for the remaining species are selected. 

We should note that we could not detect any hydrogen peroxide accumulating in the bulk solution. 

In view of the large importance of this value for applications, it was the subject of numerous studies in the 1950s and 1960s. Different reasons have been offered the influence of oxide layers present on the electrode surface the influence of traces of hydrogen peroxide accumulating in the electrolyte layer next to the electrode, and so on. The exact origin of the phenomenon has not yet been established. 

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