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.

Desdanine, an inhibitor of oxidative phosphorylation in mitochondria

1972 ◽  
Vol 18 (2) ◽  
pp. 265-269 ◽  
Author(s):  
Fritz Reusser
Keyword(s):  
Electron Transfer ◽  
Oxidative Phosphorylation ◽  
Respiratory Chain ◽  
Rat Liver ◽  
Mitochondrial Respiration ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Individual Reaction

The antibiotic, desdanine, acts as an uncoupling agent of oxidative phosphorylation in rat liver mitochondria. In addition, mitochondrial respiration is also impaired but to a lesser degree. Studies of individual reaction sequences occurring within the respiratory chain indicate that desdanine interferes with electron transfer at the flavoprotein regions associated with the oxidation of NADH and succinate. The flavoprotein region associated with the oxidation of succinate is more susceptible to desdanine than the NADH-linked flavoprotein region.

Uncoupling of oxidative phosphorylation in rat liver mitochondria by chloroethanols

1991 ◽  
Vol 59 (1-3) ◽  
pp. 203-211 ◽  
Author(s):  
Hari K. Bhat ◽  
Gregory K. Asimakis ◽  
G.A.S. Ansari
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Uncoupling Of Oxidative Phosphorylation

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.

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