scholarly journals Functional changes in rat liver mitochondria on administration of 2-methyl-4-dimethylaminoazobenzene

1984 ◽  
Vol 224 (3) ◽  
pp. 955-960 ◽  
Author(s):  
P Saikumar ◽  
C K R Kurup
Keyword(s):  
Electron Transfer ◽  
Cytochrome Oxidase ◽  
Rat Liver ◽  
Serum Cholesterol ◽  
Oxidase Activity ◽  
Mitochondrial Fraction ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Functional Changes ◽  
Succinate Oxidase

Administration of 2-methyl-4-dimethylaminobenzene in the diet (0.1%, w/w) for 85-90 days doubled the content of mitochondria in the livers of rats. The azodye was covalently bound to liver proteins, and about 15% of the amount found in liver was associated with the mitochondrial fraction. Mitochondria isolated from the livers of azodye-fed animals showed drastically lowered ability to oxidize NAD+-linked substrates. The inhibited electron-transfer step was the reduction of ubiquinone. The organelles showed a large increase in succinate oxidase activity. The activity of cytochrome oxidase and the content of cytochrome aa3 were substantially higher in these organelles. Azodye-fed animals showed depressed serum cholesterol concentrations. The content of ubiquinone in liver also registered a small increase.

Succinic and Cytochrome Oxidase Activity of Rat Liver Mitochondria After in Vitro Irradiation With Ultraviolet Light

1957 ◽  
Vol 188 (3) ◽  
pp. 547-549 ◽  
Author(s):  
Attilio Canzanelli ◽  
Rhea Sossen ◽  
David Rapport
Keyword(s):  
Cytochrome Oxidase ◽  
Ultraviolet Light ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Biological Effects ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome Oxidase Activity ◽  
Order Of Magnitude

Five per cent suspensions of rat liver mitochondria were irradiated with ultraviolet light for varying periods of time and the succinoxidase and cytochrome oxidase activity were determined. Both succinoxidase and cytochrome oxidase activity were reduced by irradiation with ultraviolet. The order of magnitude of the ultraviolet energy necessary to produce such changes is much less than that necessary to produce chemical changes in nucleic acid derivatives, and approaches the amount which has been shown to produce lethal and other biological effects.

ENZYME INHIBITION BY DERIVATIVES OF PHENOTHIAZINE

1952 ◽  
Vol 30 (6) ◽  
pp. 443-446
Author(s):  
H. B. Collier ◽  
G. M. Allenby
Keyword(s):  
Oxygen Uptake ◽  
Cytochrome Oxidase ◽  
Enzyme Inhibition ◽  
Rat Liver ◽  
Oxidase Activity ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Cytochrome Oxidase Activity ◽  
Derivatives Of

The succinoxidase activity of rat-liver mitochondria was strongly inhibited by the following compounds (concentration for 50% reduction in rate of oxygen uptake is given in brackets): phenothiazine (1.4 × 10−5 M), phenothiazine sulphoxide (2.8 × 10−5 M), and phenothiazone (5.4 × 10−5 M). Thionol was only slightly inhibitory. The cytochrome oxidase activity of mitochondria was not inhibited by any of these compounds.

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.

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