Oxidase, aerobic anaerobic

Wilmot et al. (1999) have reported high resolution crystal structures of three species relevant to understanding the chemistry of the oxidative half cycle of amine oxidases, (i) anaerobic substrate-reduced ECAO, (ii) anaerobic substrate-reduced ECAO with bound nitric oxide (an oxygen mimic) and (iii) ECAO reacted aerobically with substrate to reach an equilibrium turnover state, then cryo-trapped. In all these species, product aldehyde remains bound at the back of the substrate binding pocket and this seems to be crucial in allowing build up of intermediates. 

Berkeley96 investigated oxidase action in preparations obtained from the crystalline style of the mollusc, Saxidomus giganteus. He demonstrated the aerobic and anaerobic production of D-glucosone by separate systems, each of which comprised a component in the style and another in the diatomaceous food of the mollusc. The osone was identified through the formation of D-glucose m-nitrophenylosazone and by reduction with zinc... 

Figure 22.5 Aerobic versus anaerobic electrochemical activation of FAD-dependent oxidases.

Carbon monoxide serves as the sole carbon and energy source for the carboxydo bacteria under aerobic conditions. Using water as the oxygen donor, carbon monoxide oxidase catalyzes the hydroxylation of carbon monoxide, giving carbon dioxide or bicarbonate for assimilation. Most work has been carried out on the enzyme from Pseudomonas carboxydovorans.,ftJ7>W38 The activity of carbon monoxide oxidase is considerably stimulated upon anaerobic treatment with sulfide and dithionite, or by aerobic treatment with selenite. The binding of selenite to the oxidase specifically activates the CO — methylene blue reaction.1039 The molybdenum cofactor liberated from selenium-activated carbon monoxide oxidase does not contain selenium. Here, then, the... 

Fig. 12.6. The onset of synthesis of various mitochondrial polypeptides upon transferring anaerobically grown yeast cells to aerobic conditions. Yeast cells were grown overnight under anaerobic conditions. At time zero they were transferred to aerobic conditions, and at the indicated time periods samples of cells were removed and lysed in the presence of NaOH and mercaptoethanol. Samples containing about 50 /ig of protein were electrophoresed in a sodium dodecyl sulfate-polyacrylamide gel. The proteins were electrotransferred to nitrocellulose sheets and decorated with specific antibodies and l-labelled protein A. Paper pieces corresponding to the labelled protein spots were cut out from the immune blot and counted in a y counter. The amount of counts obtained in the samples of 8 h aerobic conditions was taken as 100%. The antibodies used were directed against the following polypeptides porin of the mitochondrial outer membrane (29 k) /8 subunit of the proton-ATPase (iS-F,) subunit IV of cytochrome c oxidase (OxIV) and subunit V of cytochrome c oxidase (OxV).

The aerobic oxidation of RAA (Figure 1) occurs rapidly when metal catalysts, particularly copper or iron, or enzymes such as ascorbic acid oxidase, polyphenol oxidase, peroxidase, and cytochrome oxidase are present. The anaerobic destruction of ascorbic acid may proceed by a variety of mechanisms that have been postulated (2,3) but not verified. 

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