Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetically engineering the heterologous bacterial host with the gene (vgb) encoding Vitreoscilla haemoglobin (VHb) has been found to provide typical advantages in growth and production, and it has generally been assumed that VHb is responsible for this effect. Here, using matched strains of Escherichia coli that bear a recombinant R-amylase gene (MK57) or the R-amylase gene and vgb (MK79), we examined this assumption. Menadione, which is known to oxidize haem proteins, was tested over a range of concentrations for its effects on growth, R-amylase production, respiration and VHb function in MK57 and MK79. Active VHb accumulated, and VHb was oxidized to the inactive ferric form with the use of menadione at the concentrations of 0.5-10 mM; concentrations that had a much smaller effect on cytochrome oxidase. This decrease in active VHb in strain MK79 was correlated with a reverse in the advantage regarding R-amylase production of MK79 over MK57 seen at a menadione concentration of 0 mM, thus linking the presence of active VHb with the increase in R-amylase production. It is concluded that vgb, and not any other Vitreoscilla DNA sequences on plasmid pMK79, is the source of the advantages in both the growth and product production of alpha-amylase in this system.
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PMID:Menadione knocks out Vitreoscilla haemoglobin (VHb): the current evidence for the role of VHb in recombinant Escherichia coli. 1265 36

Conidia of Verticillium albo-atrum Reinke and Berthold, collected from shake cultures grown in Czapek broth, were sonified for 4 or 8 minutes or ground frozen in a mortar to obtain cell-free homogenates. These were assayed for certain enzymes associated with respiratory pathways. Malic dehydrogenase was the most active, glucose-6-P and NADH dehydrogenase were less active, NADH-cytochrome c reductase, NADPH dehydrogenase, and cytochrome oxidase were low in activity, and succinic dehydrogenase and succinic cytochrome c reductase were very low to negligible in activity. No NADH oxidase activity was detected.With the exception of NADH-cytochrome c reductase and possibly succinic dehydrogenase and cytochrome c reductase, there was no evident increase in specific activity of the enzymes during germination. Some NADH-cytochrome c reductase and a small amount of succinic-dehydrogenase and cytochrome c reductase were associated with the particulate fraction from 105,000 x g centrifugation. The other enzymes, including cytochrome oxidase, almost completely remained in the supernatant fraction.Menadione and vitamin K-S(II) markedly stimulated NADH-cytochrome c reductase activity in the supernatant fraction but had much less effect on NADPH-cytochrome c reductase in this fraction or on either of these enzyme systems in the particulate fraction. Electron transport inhibitors affected particulate NADH- and NADPH-cytochrome c reductase activity but had no effect on these in the supernatant fraction.
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PMID:Relative Activities and Characteristics of Some Oxidative Respiratory Enzymes from Conidia of Verticillium albo-atrum. 1665 81

In animals, the impact of ROS production by mitochondria on cell physiology, death, disease and ageing is well recognised. In photosynthetic organisms such as higher plants, however, the chloroplast and peroxisomes are the major sources of ROS during normal metabolism and the importance of mitochondria in oxidative stress and redox signalling is less well established. To address this, the in vivo oxidation state of a mitochondrially-targeted redox-sensitive GFP (mt-roGFP2) was investigated in Arabidopsis leaves. Classical ROS-generating inhibitors of mitochondrial electron transport (rotenone, antimycin A and SHAM) had no effect on mt-roGFP oxidation when used singly, but combined inhibition of complex III and alternative oxidase by antimycin A and SHAM did cause significant oxidation. Inhibitors of complex IV and aconitase also caused oxidation of mt-roGFP2. This oxidation was not apparent in the cytosol whereas antimycin A+SHAM also caused oxidation of cytosolic roGFP2. Menadione had a much greater effect than the inhibitors, causing nearly complete oxidation of roGFP2 in both mitochondria and cytosol. A range of severe abiotic stress treatments (heat, salt, and heavy metal stress) led to oxidation of mt-roGFP2 while hyperosmotic stress had no effect and low temperature caused a slight but significant decrease in oxidation. Similar changes were observed for cytosolic roGFP2. Finally, the recovery of oxidation state of roGFP in mitochondria after oxidation by H(2)O(2) treatment was dramatically slower than that of either the cytosol or chloroplast. Together, the results highlight the sensitivity of the mitochondrion to redox perturbation and suggest a potential role in sensing and signalling cellular redox challenge.
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PMID:Monitoring the in vivo redox state of plant mitochondria: effect of respiratory inhibitors, abiotic stress and assessment of recovery from oxidative challenge. 1936 6