Microsomal electrode

The employment of cell organelles has been limited to mitochondrial and microsomal fractions (Table 15). As early as 1976, Guilbault et al. coupled pig heart mitochondrial electron transfer particles (ETP) with an oxygen electrode. This development has been further pursued by Aizawa et al. (1980c). Decoupling of the electron transfer from oxidative phosphorylation makes ETP catalyze the following reactions ... 

Fig. 105. Construction and response curve of an organelle electrode for aniline based on immobilized liver microsomes. (Redrawn from Mohr et al., 1984).

The widespread use of dehydrogenase reactions in clinical chemistry prompted further investigation of the coupling of other enzymes with the microsomal NADPH oxidase in hybrid electrodes (Schubert et al., 1982b). Thus, sensors for ATP and isocitrate have been assembled (Table 15), which indicates the usefulness of this concept. 

Isaksson, K. and Kissinger, P.T., Metabolism of physostigmine in mouse liver microsomal incubations studied by liquid chromatography with dual-electrode amperometric detection, 7. Chromatog., 419, 165, 1987. 

Fig. 9 Schematic representation of LbL films of cyt P450 and CPR on pyrolydc graphite electrodes. Films are assembled electrostatically from CPR microsomes and pure cyt P450s on polyion bilayer surface of pyrolytic graphite disk electrodes...

Fig. 11 a Background subtracted CVs in pH 7.0 buffer +0.1 M NaCl for LbL films of cyt P450 1A2 and microsomal CPR assembled on electrodes in the pesence of nitrogen and CO. b Craresponding CO dilf(Ear nce spectra of the LbL films assembled on aminosilane-fused silica slides (analogous to the assembly on electrodes) in the presence of NADPH. Reprinted with permission from the American Chemical Society, Ref. [71], Copyright 2011... 

This observation confirmed that peroxide shunt pathway was not utilized in the NNK catalysis by LbL films of cyt P450 2E1 with microsomal CPR (Scheme 1) which would have otherwise caused less peroxide level to remain in the electrolyte solution compared to that produced with just polyion or microsomal CPR electrodes. Therefore, the electrochemically driven biocatalysis should have followed the natural CPR-mediated cyt P450 catalytic pathway in the designed electrostatically... 

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