Effect of antimycin A and 2-heptyl-4-hydroxyquinoline N-oxide on the respiratory chain of submitochondrial particles of beef heart

Biochemistry ◽  
1972 ◽  
Vol 11 (7) ◽  
pp. 1150-1154 ◽  
Author(s):  
J. R. Brandon ◽  
J. R. Brocklehurst ◽  
C. P. Lee
Keyword(s):  
Respiratory Chain ◽  
Beef Heart ◽  
Antimycin A ◽  
Submitochondrial Particles

scholarly journals NADH- and NADPH-dependent lipid peroxidation in bovine heart submitochondrial particles. Dependence on the rate of electron flow in the respiratory chain and an antioxidant role of ubiquinol

1980 ◽  
Vol 192 (3) ◽  
pp. 853-860 ◽  
Author(s):  
R Takayanagi ◽  
K Takeshige ◽  
S Minakami
Keyword(s):  
Lipid Peroxidation ◽  
Respiratory Chain ◽  
Electron Flow ◽  
Antimycin A ◽  
Submitochondrial Particles ◽  
Bovine Heart ◽  
Malondialdehyde Formation ◽  
Low Rate ◽  
Liquid Peroxidation

Malondialdehyde formations by bovine heart submitochondrial particles supported by NADH or NADPH in the presence of ADP and FeCl3 was studied. The NADH-dependent reaction was maximal at very low rate of electron input from NADH to the respiratory chain and it decreased when the rate became high. The reaction was stimulated by rotenone and inhibited by antimycin A when the input was fast, whereas it was not affected by the inhibitors when the input was slow. The input rate of the electrons from NADPH was also so low that the reaction supported by NADPH was not affected by the inhibitors. Most of the endogenous ubiquinone in the particles treated with antimycin A was reduced by NADH even in the presence of ADP-Fe3+ chelate, but uniquinone was not reduced by NADPH when ADP-Fe3+ was present. Succinate strongly inhibited both NADH- and NADPH-dependent lipid peroxidation. The inhibition was abolished when uniquinone was removed from the particles, and it appeared again when uniquinone was reincorporated into the particles. Reduced uniquinone-2 also inhibited the peroxidation, but duroquinol, which reduces cytochrome b without reducing endogenous uniquinone, did not. Thus the malondialdehyde formation appeared to be inversely related to the extent of the reduction of endogenous uniquinone. These observations suggest that both NADH- and NADPH-dependent liquid-peroxidation reactions are closely related to the respiratory chain and that the peroxidation is controlled by the concentration of reduced ubiquinone.

scholarly journals A kinetic analysis of the changes in fluorescence on the interaction of 8-anilinonaphthalene-l-sulphonate with submitochondrial particles

1976 ◽  
Vol 158 (2) ◽  
pp. 295-305 ◽  
Author(s):  
N Gains ◽  
A P Dawson
Keyword(s):  
Kinetic Analysis ◽  
Mitochondrial Membrane ◽  
Antimycin A ◽  
Submitochondrial Particles ◽  
Submitochondrial Particle ◽  
Fluorescence Change

A comparison of the fluorescence change on the addition of 8-anilinonaphthalene-1-sulphonate to succinate-energized submitochondrial particles with that on the addition of succinate to submitochondrial particles incubated with 8-anilinonaphthalene-1-sulphonate shows that these changes in fluorescence may be explained solely in terms of 8-anilinonaphthalene-1-sulphonate binding. This comparison does not support the proposal of an 8-anilinonaphthalene-1-sulphonate-monitored change in the conformation of submitochondrial-particle membranes [Brocklehurst, Freedman, Hancock & Radda (1970) Biochem. J.116, 721-731]. The biphasic nature of the decrease in fluorescence, which was found to follow the addition of uncoupler to submitochondrial particles incubated with ATP or succinate, or of antimycin A to submitochondrial particles incubated with succinate, does not support the existence of ‘aplectic’ and ‘symplectic’ states of the mitochondrial membrane [Barrett-Bee & Radda (1972) Biochim, Biophys. Acta 267, 211-215].

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