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Lipid peroxidation and the reduction of ADP-Fe3+ chelate by NADH-ubiquinone reductase preparation from bovine heart mitochondria.

ABSTRACT: The NADH-ubiquinone reductase preparation (Complex I) of bovine hart mitochondria catalysed in the presence of reduced coenzymes and ADP-Fe3+ the lipid peroxidation of liposomes prepared from mitochondrial lipids. The apparent Km values for the coenzymes and the optimal pH of the reactions agreed well with those of the lipid peroxidation of the submitochondrial particles treated with rotenone. On assay of the reduction of ADP-Fe3+ chelate by the reduction of cytochrome c in the presence of superoxide dismutase and antimycin A or by the oxidation of reduced coenzymes, the reactions were not affected by rotenone but were inhibited by thiol-group inhibitors. The properties of the ADP-Fe3+ reductase activity were highly consistent with those of the lipid-peroxidation reaction. These observations suggest that electrons from reduced coenzymes are transferred to ADP-Fe3+ chelate from a component between a mercurial-sensitive site and the rotenone-sensitive one of the NADH dehydrogenase and that the reduction of ADP-Fe3+ chelate by the NADH dehydrogenase is an essential step in the lipid peroxidation.

SUBMITTER: Takeshige K

PROVIDER: S-EPMC1162410 | biostudies-other | 1980 Dec

REPOSITORIES: biostudies-other

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The mechanism of superoxide production by NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria.

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| S-EPMC1472492 | biostudies-literature

NADH- and NADPH-dependent formation of superoxide anions by bovine heart submitochondrial particles and NADH-ubiquinone reductase preparation.

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| S-EPMC1161027 | biostudies-other

The structure and subunit composition of the particulate NADH-ubiquinone reductase of bovine heart mitochondria.

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Inhibition of Mitochondria NADH–Ubiquinone Oxidoreductase (Complex I) Sensitizes the Radioresistant Glioma Cells to Radiation

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2020-01-15 | GSE143609 | GEO

NADH:ubiquinone oxidoreductase from bovine mitochondria. cDNA sequence of a 19 kDa cysteine-rich subunit.

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| S-EPMC1151184 | biostudies-other

Nitric oxide inhibits mitochondrial NADH:ubiquinone reductase activity through peroxynitrite formation.

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Ubiquinone reduction pattern in pigeon heart mitochondria. Identification of three distinct ubiquinone pools.

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| S-EPMC1145104 | biostudies-other

Cytochrome b5 and NADH cytochrome b5 reductase: genotype-phenotype correlations for hydroxylamine reduction.

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Cloning and characterization of a maize cytochrome-b5 reductase with Fe3+-chelate reduction capability.

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| S-EPMC1220078 | biostudies-other

Kinetics and regulation of mammalian NADH-ubiquinone oxidoreductase (Complex I).

Project description:NADH-ubiquinone oxidoreductase (Complex I, European Commission No. 1.6.5.3) is one of the respiratory complexes that generate the proton-motive force required for the synthesis of ATP in mitochondria. The catalytic mechanism of Complex I has not been well understood, due to the complicated structure of this enzyme. Here, we develop a kinetic model for Complex I that accounts for electron transfer from NADH to ubiquinone through protein-bound prosthetic groups, which is coupled to the translocation of protons across the inner mitochondrial membrane. The model is derived based on the tri-bi enzyme mechanism combined with a simple model of the conformational changes associated with proton transport. To study the catalytic mechanism, parameter values are estimated by analyzing kinetic data. The model is further validated by independent data sets from additional experiments, effectively explaining the effect of pH on enzyme activity. Results imply that matrix pH significantly affects the enzyme turnover processes. The overall kinetic analysis demonstrates a hybrid ping-pong rapid-equilibrium random bi-bi mechanism, consolidating the characteristics from previously reported kinetic mechanisms and data.

| S-EPMC2931722 | biostudies-literature

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