Cytochrome peroxidase, activity increase

When air is admitted to an anaerobic yeast culture, respiration reaches normal values within about 4 hours [21]. The cytochrome bands at 556 mfi and 580 m/i are replaced by the bands of cytochromes c, b, and a [19]. Additionally, succinate-cytochrome c reductase activity rises. Catalase and cytochrome peroxidase activities increase over 30-fold, as do NADH-cytochrome c reductase, lactate-cytochrome c reductase, and a-glycerophosphate-cytochrome c reductase. Enzymes of the tricarboxylic acid cycle also increase in activity [21]. 

Chen et al. [47] demonstrated that the reaction of HOC1 with cytochrome c increased cytochrome peroxidase activity by the oxidation of the methionine residue. Methionine oxidation also significantly decreased the efficiency of cytochrome c as a mitochondrial electron carrier. HOC1, HOBr, and HOI are also able to oxidize (Fen)cytochrome c [48],... 

O Donnell et al. [70] found that LOX and not cyclooxygenase, cytochrome P-450, NO synthase, NADPH oxidase, xanthine oxidase, ribonucleotide reductase, or mitochondrial respiratory chain is responsible for TNF-a-mediated apoptosis of murine fibrosarcoma cells. 15-LOX activity was found to increase sharply in heart, lung, and vascular tissues of rabbits by hypercholesterolemia [71], Schnurr et al. [72] demonstrated that there is an inverse regulation of 12/15-LOXs and phospholipid hydroperoxide glutathione peroxidases in cells, which balanced the intracellular concentration of oxidized lipids. 

The modified electrode, in turn, enhances Mb to catalyze the reduction of H2O2. Addition of H202 increases in the cathodic peak intensity for the modified electrode. This electrochemical response is specific for the Mb silver NP modified electrode because no signals are observed for either the bare electrode or an electrode with only a silver NP film. A Michaelis-Menten analysis demonstrates that the modified electrode shows higher affinity for H202 than other gold-cytochrome c and gold-horseradish peroxidase modified electrodes. The apparent enhanced catalytic activity... 

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