Effect of illumination on the redox state of cytochrome c oxidase in wheat leaves in vivo

1986 ◽  
Vol 5 (4) ◽  
pp. 259-261 ◽  
Author(s):  
M. S. Naik ◽  
J. D. Nicholas
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Redox State ◽  
Wheat Leaves

Reduction of cytochrome-c oxidase copper precedes failing cerebral O2 utilization in fluorocarbon-perfused cats

1996 ◽  
Vol 271 (2) ◽  
pp. H579-H587 ◽  
Author(s):  
R. Stingele ◽  
B. Wagner ◽  
M. V. Kameneva ◽  
M. A. Williams ◽  
D. A. Wilson ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Redox State ◽  
Near Infrared ◽  
Hypoxic Conditions ◽  
Sagittal Sinus ◽  
Tissue Po2 ◽  
Relationship Of ◽  
The Relationship

We determined the relationship of the low-potential copper (CuA) redox state of cytochrome-c oxidase to the brain tissue PO2 (PtiO2) and global cerebral O2 consumption (CMRO2) in vivo. The redox state of cytochrome-c oxidase copper was monitored in perfluorocarbon-exchanged cats under normoxic and graded hypoxic conditions with use of near-infrared spectroscopy. Continuous spectra ranging from 730 to 960 nm were acquired, and the change in copper redox state was assessed by the absorption changes at 830 nm. PtiO2 was measured with O2-sensitive electrodes implanted into the cortex, and CMRO2 was determined by sampling arterial and superior sagittal sinus perfusate and by measuring blood flow with radiolabeled microspheres. As PtiO2 decreased with hypoxia, the CuA of cytochrome-c oxidase became progressively reduced, whereas the CMRO2 was unchanged during the initial stages of hypoxia. Only with severe hypoxia, did CMRO2 and the amplitude of somatosensory evoked potentials decrease. We conclude that the CuA site of cytochrome-c oxidase is involved in a regulatory adjustment that helps maintain CMRO2 constant.

Spectrophotometric monitoring of O2 delivery to the exposed rat kidney

1981 ◽  
Vol 241 (3) ◽  
pp. F257-F262 ◽  
Author(s):  
R. S. Balaban ◽  
A. L. Sylvia
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Redox State ◽  
Rat Kidney ◽  
Arterial Oxygen ◽  
Anesthetized Rats ◽  
Arteriovenous Shunts ◽  
Wide Range

Optical spectrophotometry was used to measure changes in the oxidation-reduction state of cytochrome c oxidase in the in situ rat kidney. Alterations in the redox state of cytochrome c oxidase were monitored during variations in the amount of oxygen being delivered to the animal. Spectral analyses were performed on whole kidney, cortical tubule suspensions, and blood (the latter flowing freely through surgically implanted femoral arteriovenous shunts). Reaction spectra identified the location of the absorption maxima for reduced cytochrome c oxidase to be at approx. 605 nm. Additional spectral analysis indicated that hemoglobin oxygenation-deoxygenation changes had minimal artifactual interference on the cytochrome redox signals. The present results indicate that mitochondrial cytochrome c oxidase is not maximally oxidized in the in situ kidney of anesthetized rats at arterial oxygen in the in situ kidney of anesthetized rats at arterial oxygen tensions within the normal physiological range. The redox state of the enzyme in vivo is altered by changes in the level of inspired oxygen over a wide range. The current data are consistent with the existence of nonuniform regions of aerobic respiration occurring in the in situ kidney.

scholarly journals The isoforms of yeast cytochrome c oxidase subunit V alter the in vivo kinetic properties of the holoenzyme

1991 ◽  
Vol 266 (7) ◽  
pp. 4180-4186
Author(s):  
R A Waterland ◽  
A Basu ◽  
B Chance ◽  
R O Poyton
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Kinetic Properties ◽  
Oxidase Subunit

Kinetics of the cytochrome c oxidase and reductase reactions in energized and de-energized mitochondria

1977 ◽  
Vol 55 (7) ◽  
pp. 706-713 ◽  
Author(s):  
Lars Chr. Petersen ◽  
Hans Degn ◽  
Peter Nicholls
Keyword(s):  
Steady State ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Oxygen Concentration ◽  
Respiration Rate ◽  
Redox State ◽  
Rat Liver Mitochondria ◽  
Excess Oxygen ◽  
Succinate Oxidation ◽  
State Reduction

1. Coupled, cytochrome-c-depleted ('stripped') rat liver mitochondria reducing oxygen in the presence of exogenous cytochrome c, with succinate or ascorbate as substrates, show marked declines in the steady-state reduction of cytochrome c in excess oxygen on addition of uncouplers. Calculated ratios of maximal turnover in the uncoupled state and in the energized state for the cytochrome c oxidase (EC 1.9.3.1) reaction lie between 3 and 6, as obtained with reconstituted oxidase-containing vesicles. The succinate-cytochrome c reductase activity in such mitochondria shows a smaller response to uncoupler than that of the oxidase.2. The respiration rates of uncoupled mitochondria oxidizing ascorbate in the presence of added cytochrome c follow a Michaelis–Menten relationship with respect to oxygen concentration, in accordance with the pattern found previously with the solubilized oxidase. But succinate oxidation tends to give nonlinear concave-upward double-reciprocal plots of respiration rate against oxygen concentration, in accordance with the pattern found previously with intact uncoupled mitochondria.3. From simultaneous measurements of cytochrome c steady-state reduction, respiration rate, and oxygen concentration during succinate oxidation under uncoupled conditions it is found that at full reduction of cytochrome c, apparent Km for oxygen is 0.9 μM and the maximal oxidase (aa3) turnover is 400 s−1 (pH 7.4, 30 °C).4. The redox state of cytochrome c in uncoupled systems reflects a simple steady state; the redox state of cytochrome c in energized systems tends towards an equilibrium condition with the terminal cytochrome a3, whose apparent potential under these conditions is more negative than that of cytochrome c.

Response of Heme Symmetry to the Redox State of Bovine Cytochrome c Oxidase

Biochemistry ◽  
2018 ◽  
Vol 57 (28) ◽  
pp. 4105-4113
Author(s):  
Katarina Kopcova ◽  
Ludmila Blascakova ◽  
Tibor Kozar ◽  
Daniel Jancura ◽  
Marian Fabian
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Redox State

Exposure of Bacillus subtilis to silver inhibits activity of cytochrome c oxidase in vivo via interaction with SCO, the CuA assembly protein

Metallomics ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 735-744 ◽  
Author(s):  
Shina Hussain ◽  
Diann Andrews ◽  
Bruce C. Hill
Keyword(s):  
Bacillus Subtilis ◽  
Cytochrome C ◽  
Antimicrobial Agent ◽  
Cytochrome C Oxidase ◽  
Medicinal Use

Silver has long been used as an antimicrobial agent in general and medicinal use.

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