scholarly journals The effect of cytochrome c and its ‘dimer’ on electron transfer and energy transformation

1972 ◽  
Vol 126 (3) ◽  
pp. 709-716 ◽  
Author(s):  
T. Shur-Perek ◽  
Y. Avi-Dor
Keyword(s):  
Electron Transfer ◽  
Electron Transport ◽  
Cytochrome C ◽  
Proton Translocation ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Energy Transformation ◽  
Early Step ◽  
Electron Carrier ◽  
Stimulation Of

A preparation that contained cytochrome c, mainly in the form of its ‘dimer’, was studied and compared with native cytochrome c with respect to its ability to support electron transfer and energy transformation in cytochrome c-depleted rat liver mitochondria. When the depleted mitochondria were titrated with either cytochrome c or the ‘dimer’, the extent of coupling between respiration and phosphorylation was enhanced, as manifested by an increase in the P/O ratio. The ‘dimer’ was relatively ineffective as an electron carrier in the respiratory system, but it was as effective as cytochrome c in reconstitution of oxidative phosphorylation in depleted mitochondria. Addition of ‘dimer’ to the depleted mitochondria, in the presence of a low, non-saturating concentration of cytochrome c, increased the P/O ratio without concomitant stimulation of respiration. Both cytochrome c and the ‘dimer’ stimulated spontaneous swelling and electron transport-driven proton translocation in depleted mitochondria. The pattern of action of cytochrome c and its ‘dimer’ is in accord with the assumption that they affect an early step in energy conservation.

scholarly journals Proton translocation by the mitochondrial cytochrome b-c1 complex is inhibited by NN′-dicyclohexylcarbodi-imide

1982 ◽  
Vol 206 (2) ◽  
pp. 419-421 ◽  
Author(s):  
B D Price ◽  
M D Brand
Keyword(s):  
Electron Transport ◽  
Cytochrome Oxidase ◽  
Cytochrome B ◽  
Rat Liver ◽  
Proton Translocation ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Mitochondrial Cytochrome ◽  
Low Concentrations ◽  
Mitochondrial Cytochrome B

NN'-Dicyclohexylcarbodi-imide at low concentrations decreases the H+/2e ratio for rat liver mitochondria over the span succinate to oxygen from 5.9 +/- 0.3 (mean +/- S.E.M.) to 4.0 +/- 0.1 and for the cytochrome b-c1 complex from 3.8 +/- 0.2 to 1.9 +/- 0.1, but has little effect on the H+/2e ratio of cytochrome oxidase. The decrease in stoicheiometry is due, not to uncoupling or inhibition of electron transport, but to inhibition of proton translocation. NN'-Dicyclohexylcarbodi-imide thus ‘decouples’ proton translocation in the cytochrome b-c1 complex.

scholarly journals Sensitivity to NN'-dicyclohexylcarbodi-imide of proton translocation by mitochondrial NADH:ubiquinone oxidoreductase

1986 ◽  
Vol 237 (3) ◽  
pp. 927-930 ◽  
Author(s):  
P J Honkakoski ◽  
I E Hassinen
Keyword(s):  
Electron Transfer ◽  
Respiratory Chain ◽  
Proton Translocation ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Proton Extrusion ◽  
Ferricyanide Reduction ◽  
Isolated Rat Liver ◽  
Isolated Rat

Proton extrusion during ferricyanide reduction by NADH-generating substrates or succinate was studied in isolated rat liver mitochondria with the use of optical indicators. NN'-Dicyclohexylcarbodi-imide (DCCD) caused a decrease of 84% in the H+/e- ratio of NADH:cytochrome c reduction, but a decrease of only 49% in that of succinate:cytochrome c reduction, even though electron transfer was decreased equally in both spans. The data indicate that a DCCD-sensitive channel operates in the NADH:ubiquinone oxidoreductase region of the respiratory chain.

scholarly journals Cytochrome C And The Role Of Zinc Ions In Electron Transport In Rat Liver Mitochondria

2005 ◽  
Vol 18 (1) ◽  
Author(s):  
BI Kukoyi ◽  
Z Guan ◽  
LC Costello ◽  
RB Franklin
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Zinc Ions

Arsenate Uncoupling of Oxidative Phosphorylation in Isolated Plant Mitochondria

1976 ◽  
Vol 3 (2) ◽  
pp. 153 ◽  
Author(s):  
W.A Wickes ◽  
J.T Wiskish
Keyword(s):  
Electron Transfer ◽  
Oxidative Phosphorylation ◽  
Plant Mitochondria ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Transfer Processes ◽  
Uncoupling Of Oxidative Phosphorylation ◽  
Electron Transfer Processes ◽  
Stimulation Of ◽  
Malate Oxidation

The uncoupling by arsenate of beetroot and cauliflower bud mitochondria showed the following characteristics: (1) arsenate stimulation of respiration above the rate found with phosphate; (2) inhibition of arsenate-stimulated respiration by phosphate; (3) enhancement of arsenate-stimulated respiration by ADP; (4) only partial prevention of this ADP-enhanced respiration by atractyloside; (5) inhibition by oligomycin of the arsenate-stimulated respiration back to the phosphate rate; and (6) the absence of any stimulatory effect of ADP in the presence of oligomycin. These results are qualitatively analogous to those reported for arsenate uncoupling in rat liver mitochondria. Arsenate stimulated malate oxidation, presumably by stimulating malate entry, in both beetroot and cauliflower bud mitochondria; however, high rates of oxidation, and presumably entry, were only sustained with arsenate in beetroot mitochondria. NADH was oxidized rapidly in cauliflower bud mitochondria in the presence of arsenate, showing that arsenate did not inhibit electron transfer processes.

Effects of 5-5'-Diphenyl-2-thiohydantoin (DPTH) and Thyroxine on the Ultrastructure and Chemical Composition of Rat Liver

1971 ◽  
Vol 29 ◽  
pp. 570-571
Author(s):  
E. A. Elfont ◽  
R. B. Tobin ◽  
D. G. Colton ◽  
M. A. Mehlman
Keyword(s):  
Chemical Composition ◽  
Rat Liver ◽  
Future Study ◽  
Mode Of Action ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Effective Inhibitor ◽  
Biochemical Effects ◽  
Glycerophosphate Dehydrogenase ◽  
Stimulation Of

Summary5,-5'-diphenyl-2-thiohydantoin (DPTH) is an effective inhibitor of thyroxine (T4) stimulation of α-glycerophosphate dehydrogenase in rat liver mitochondria. Because this finding indicated a possible tool for future study of the mode of action of thyroxine, the ultrastructural and biochemical effects of DPTH and/or thyroxine on rat liver mere investigated.Rats were fed either standard or DPTH (0.06%) diet for 30 days before T4 (250 ug/kg/day) was injected. Injection of T4 occurred daily for 10 days prior to sacrifice. After removal of the liver and kidneys, part of the tissue was frozen at -50°C for later biocheailcal analyses, while the rest was prefixed in buffered 3.5X glutaraldehyde (390 mOs) and post-fixed in buffered 1Z OsO4 (376 mOs). Tissues were embedded in Araldlte 502 and the sections examined in a Zeiss EM 9S.Hepatocytes from hyperthyroid rats (Fig. 2) demonstrated enlarged and more numerous mitochondria than those of controls (Fig. 1). Glycogen was almost totally absent from the cytoplasm of the T4-treated rats.

scholarly journals Inhibition by dicyclohexylcarbodiimide of proton ejection but not electron transfer in rat liver mitochondria.

1984 ◽  
Vol 259 (21) ◽  
pp. 13017-13020
Author(s):  
L Clejan ◽  
C G Bosch ◽  
D S Beattie
Keyword(s):  
Electron Transfer ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria

Reversal of mitochondrial swelling associated with fatty acid oxidation. II. Effects of cytochrome c and carnitine on contraction of fatty acid swollen mitochondria

1968 ◽  
Vol 46 (9) ◽  
pp. 1151-1160 ◽  
Author(s):  
Misako Nakatani ◽  
W. C. McMurray
Keyword(s):  
Fatty Acid ◽  
Cytochrome C ◽  
Energy Requirement ◽  
Liver Mitochondria ◽  
High Energy ◽  
Fatty Acyl ◽  
Water Soluble ◽  
Rat Liver Mitochondria ◽  
Acid Oxidation ◽  
Swelling Agent

Rat liver mitochondria undergo reversible swelling in the presence of a fatty acyl CoA generating system. Contraction of the swollen mitochondria was observed on the addition of either carnitine or cytochrome c. At low concentrations the two agents acted synergistically. At high concentrations cytochrome c completely replaced the requirement for carnitine.Cytochrome c also promoted the contraction of mitochondria swollen in the presence of fatty acid alone, provided that either ATP or ADP was added to initiate the contraction. The stimulation by cytochrome c was greater in the presence of ADP, and the contraction was more sensitive to respiratory inhibitors or dinitrophenol but was less sensitive to oligomycin than in the presence of ATP. Studies of the metabolism of 14C-labelled palmitate during cytochrome c induced contraction showed that decreases in mitochondrial-bound fatty acid and corresponding increases in water-soluble metabolites coincided with the reversal of swelling. The results indicated that the energy requirement for mitochondrial contraction in the presence of cytochrome c was provided by generation of high-energy intermediates coupled to oxidation of the fatty acid swelling agent.

Cytochrome c release from rat liver mitochondria is compromised by increased saturated cardiolipin species induced by sucrose feeding

2015 ◽  
Vol 309 (9) ◽  
pp. E777-E786 ◽  
Author(s):  
Angélica Ruiz-Ramírez ◽  
Miguel-Angel Barrios-Maya ◽  
Ocarol López-Acosta ◽  
Dora Molina-Ortiz ◽  
Mohammed El-Hafidi
Keyword(s):  
Cytochrome C ◽  
Superoxide Radical ◽  
Lipid Membrane ◽  
Liver Mitochondria ◽  
Membrane Lipid ◽  
Rat Liver Mitochondria ◽  
Ros Generation ◽  
Cytochrome C Release ◽  
Mitochondrial Inner Membrane ◽  
Sucrose Feeding

Cytochrome c release from mitochondria has been described to be related to reactive oxygen species (ROS) generation. With ROS generation being increased in fatty liver from sucrose-fed (SF) rats, we hypothesized that cytochrome c release might be positively associated with H2O2 generation from SF mitochondria. Surprisingly, cytochrome c release from mitochondria of SF liver was found to be significantly lower compared with control (C) mitochondria oxidizing pyruvate/malate or succinate. Exposure of mitochondria to exogenous superoxide radical generated by the xanthine/xanthine oxidase system elicits a dose-response cytochrome c release in both control and SF mitochondria, but cytochrome c release remains lower in SF mitochondria compared with C mitochondria. Furthermore, the addition of ebselen, PEG-catalase, or catalase, a H2O2 scavenger, significantly reduces cytochrome c release from C and SF mitochondria. Our results suggest that both intra- and extramitochondrial H2O2 are involved in cytochrome c release, but the persisting difference between C and SF levels can be attributed to the differences in cardiolipin compositions. Indeed, the ratio of palmitic acid-rich cardiolipin species was found to be increased in lipid membrane from SF mitochondria compared with C mitochondria, whereas that of linoleic acid-rich cardiolipin species was found decreased. In addition, the content of tafazzin, a protein responsible for cardiolipin remodeling, was decreased in SF mitochondria. Therefore, we conclude that the changes observed in the composition of cardiolipin molecular species in SF mitochondria may be involved in cytochrome c interaction with mitochondrial inner membrane lipid and in its reduced release from SF mitochondria.

Sign in / Sign up

Export Citation Format

Share Document