Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Electron Transport Complex I”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1978

Reconstitution of escherichia coli succinoxidase from soluble components.

1. The membrane-bound succinoxidase of Escherichia coli was fractionated with deoxycholate into three soluble components, viz. succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase complex, and a factor identified as a phospholipid-containing component. 2. The dehydrogenase and cytochrome oxidase complexes were partially purified by filtration on Amicon membranes, Sepharose 4B chromatography, and sucrose gradient centrifugation. 3. Reconstitution of membranous succinoxidase, which catalyzes the oxidation of succinate by molecular oxygen by an integrated CN(-)-sensitive pathway, was achieved by mixing the soluble succinate dehydrogenase.cytochrome b1 complex with the soluble cytochrome oxidase complex in the presence of deoxycholate and then removing the detergent by gel filtration on Sephadex G-75. The phospholipid-containing factor stimulated the formation of succinoxidase by about 100% over that observed with the two complexes. 4. Isopycnic sucrose gradient centrifugation of succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase, and the reconstituted succinoxidase gave buoyant densities (p value) as 1.167, 1.229, and 1.194, respectively. 5. Electron microscopic evidence is presented for the vesicular nature of the reconstituted succinoxidase.

Cell Membrane↗
PubMed1979

[Role of planar cobalt chelate complexes as shunting agents in the electron transport chain of mitochondria].

It was shown that planar cobalt chelate complexes catalyze oxidation of NADH and hexahydroubiquinole Q4H2 by air oxygen. The most active agent--perchlorate of the cobalt complex 1, 2, 3, 7, 8, 12, 13, 17, 18, 19-decamethyloctadehydrocorrin--is capable of shunting the electron transfer chain of rat liver mitochondria and beef heart submitochondrial particles, catalyzing electron transfer from CoQ directly to the oxygen.

Animals↗
PubMed1976

Fusion of phospholipid vesicles reconstituted with cytochrome c oxidase and mitochondrial hydrophobic protein.

Reconstituted cytochrome oxidase liposomes were fused with liposomes reconstituted with mitochondrial hydrophobic protein, which acts as a membrane-bound uncoupler of cytochrome oxidase. Fusion was assayed by the loss of respiratory control of cytochrome oxidase as measured by the increased rate of ascorbate oxidation induced by hydrophobic protein when both proteins shared the same vesicles. Fusion was dependent on the presence of phosphatidylserine in the liposomes Ca++ in the aqueous medium. Phosphatidylcholine-phosphatidylserine liposomes required higher concentrations of phosphatidylserine and Ca++ than did phosphatidylethanolamine-phosphatidylserine liposomes. Cytochrome oxidase vesicles containing high concentrations of phosphatidylserine showed little or no respiratory control, while those with lower concentrations showed high respiratory control; respiratory control could be induced by fusing cytochrome oxidase vesicles containing high phosphatidylserine with protein-free liposomes containing low phosphatidylserine concentration. If cytochrome oxidase vesicles and hydrophobic protein vesicles were prefused separately for 15 min, they lost the ability to fuse upon being subsequently mixed together. The reconstituted vesicles had diameters of about 200 A; fusion yielded vesicles with diameters in excess of 1000 A.

Animals↗
PubMed1977

The quatenary structure of Pseudomonas cytochrome oxidase studied by electron microscopy.

Pseudomonas cytochrome oxidase (EC 1.9.3.2) was studied by negative staining in the electron microscope. The best resolution was obtained with uranyl oxalate (pH 6.0) as negative stain. Electron micrographs confirm the idea of the dimeric structure of the enzyme. A rough model of cytochrome oxidase was constructed based on different projections of the molecule seen in the electron micrographs. In this model the subunits are identical and sterically equivalent.

Electron Transport Complex IV↗
PubMed1975

Microbody of methanol-grown yeasts. Localization of catalase and flavin-dependent alcohol oxidase in the isolated microbody.

Profuse appearance of microbodies was observed in the cells of methanol-utilizing yeasts in connection with the enhanced catalase activity. These microbodies were isolated successfully by means of sucrose gradient centrifugation from the methanol-grown cells of Kloeckera sp. no. 2201. Localization of a flavin-dependent alcohol oxidase as well as characteristic microbody enzymes (catalase and D-amino acid oxidase) were ascertained in the isolated microbodies, whereas formaldehyde and formate dehydrogenases were detected in the cytoplasmic region. Localization of catalase in the isolated microbody was also demonstrated by the cytochemical technique with 3,3'-diaminobenzidine.

Alcohol Oxidoreductases↗
PubMed1977

[Electron-cytochemical and morphometric study of the activity of several enzymes in thyrocyte metochondria during malignant degeneration].

Cytochrome oxidase and succinic dehydrogenase activities were studied in the mitochondria of rat thyroid cell during experimental malignization by means of the electron-cytochemical and morphometric methods. The activity of these enzymes in the mitochondria changed depending on the stage of malignization: at the early stages it approached the normal activity, and at the later stages (precancer)--it decreased and approached the mitochondrial activity of cancer cells. A sharp decrease in the activity of the enzymes under study in the morphologically changed mitochondria of cancer cells may characterize their qualitative changes.

Animals↗
PubMed1977

[Myocardial function in patients with congenital pulmonary valve stenosis].

The studies of metabolism and morphology of the myocardium, and of ECG parameters in 72 patients with valvular pulmonary stenosis conducted with biopsy and autopsy material has demonstrated that while the workload on the right ventricle grows and the severity of the pathological process increases, the oxidative capacity of the myocardium also increase, the indices of its energy supply decrease, the degree of myocytes hypertrophy grows, and the number of mitochondria and the coefficient of their energy efficacy decrease. A correlation was established between the degree of these changes and the severity of electrocardiographic signs of hypertrophy and disorders in the repolarization process in the right ventricle.

Adenine Nucleotides↗
PubMed1978

Structure and orientation of cytochrome c oxidase in crystalline membranes. Studies by electron microscopy and by labeling with subunit-specific antibodies.

The structure and the orientation of cytochrome c oxidase molecules in crystalline cytochrome c oxidase membranes (Vanderkooi, G., Senior, A.E., Capaldi, R.A., and Hayashi, H. (1972) Biochim. Biophys. Acta 274, 38-48) were studied by image analysis of electron micrographs and by reacting the crystalline preparations with immune gamma-globulins against individual cytochrome c oxidase subunits. Binding of gamma-globulins to the membranes was detected by the following two methods: (a) electrophoretic identification of gamma-globulin polypeptides in the washed membranes; (b) electron microscopic examination of the negatively stained membranes. The membranes bound immune gamma-globulins against subunit IV (which faces the matrix side in intact mitochondria) but failed to bind immune gamma-globulins against subunits II + III (which face the outer side of the inner membrane in intact mitochondria). In contrast, solubilized cytochrome c oxidase bound either of the two immune gamma-globulins. All cytochrome c oxidase molecules in the crystalline membranes are thus asymmetrically arranged so that subunit IV faces outward and subunits II + III face toward the interior. This orientation is opposite to that found with intact mitochondria. The data also suggest that the crystalline membranes form closed vesicles which are impermeable to externally added gamma-globulins.

Animals↗
PubMed1979

Calcium-induced fusion of proteoliposomes and protein-free liposomes. Effect of their phosphatidylethanolamine content on the structure of fused vesicles.

The acidic phospholipid cardiolipin was shown to be very efficient in promoting calcium-induced fusion of proteoliposomes. The degree of fusion was dependent on the phosphatidylethanolamine content of the vesicles. Addition of CaCl2 to proteoliposomes containing phosphatidylcholine and cardiolipin but without phosphatidylethanolamine did not induce fusion. Fusion of cytochrome oxidase vesicles, containing less than 50 mol% phosphatidylethanolamine resulted in monolamellar vesicles with a diameter of about 200 nm. The vesicles could be induced to fuse further by establishing an osmotic pressure across their membranes. When proteoliposomes containing more than 50 mol% phosphatidylethanolamine were fused, large vesicles with a diameter exceeding 1 micrometer were formed. They appeared in the electron microscope as a mixture of multilamellar and monolamellar vesicles. Fusion of corresponding liposomes resulted in formation of even larger structures appearing as dense multilamellar bodies and paracrystalline honeycomb-like lattices.

Calcium↗
PubMed1977

Mitochondrial biogenesis in cultured animal cells. I. Effect of chloramphenicol on morphology and mitochondrial respiratory enzymes.

The effects of chloramphenicol on the morphology and respiratory enzymes of BHK-21 cells in spinner culture have been examined with time. Cells treated with chloramphenicol double twice before growth ceases; these cells have increased size as measured by several techniques. Mitochondria are enlarged and appear to degenerate with prolonged treatment. Cytochrome c oxidase and succinate cytochrome c reductase activities are reduced while there is no decrease in the activities of monoamine oxidase, glutamate dehydrogenase or NADPH-cytochrome c reductase. Cytochromes aa3 and b disappear on treatment while cytochromes c + c1 appears to be unaffected. All these effects are reversible if chloramphenicol is removed within a limited period of time.

Cell Division↗
PubMed1975

Calcium and pancreatic secretion. I. Subcellular distribution of calcium and magnesium in the exocrine pancreas of the guinea pig.

The distribution of calcium and magnesium has been studied in the acinar cells of the pancreas of the guinea pig. Most of the magnesium was found to be associated with the rough microsomes (probably bound to the ribosomes) and with the postmicrosomal supernate. In contrast, calcium was distributed among all the particulate fractions, primarily the mitochondria, microsomes (especially smooth surfaced), zymogen granules, and the plasmalemma, and was low in the postmicrosomal supernate. Most of the calcium recovered in the particulate fractions was found to be membrane bound. The highest concentrations were found in the membranes of the zymogen granules and in the plasmalemma. By means of control experiments using -45Ca as the tracer, it was established that a considerable redistribution of calcium occurs during homogenization and cell fractionation. At least some of the resulting artifacts were estimated quantitatively and the data were corrected accordingly. The biochemical results were confirmed with the cytochemical antimonate technique carried out on the tissue as well as on isolated fractions. The role of calcium associated with the zymogen granules and with their limiting membranes is discussed in relation to the architecture of the granule and to the functionality of the pancreatic juice.

Animals↗
PubMed1976

Characterization of nuclear membranes and endoplasmic reticulum isolated from plant tissue.

Nuclei, nuclear membranes and rough endoplasmic reticulum (rER) were isolated from onion root tips and stems. Structural preservation and purity of the fractions was determined by electron microscopic and biochemical methods. Gross compositional data (protein, phospholipid, nonpolar lipids, sterols, RNA, DNA), phospholipid and fatty acid patterns, enzyme activities (ATPases, ADPase, IDPase, glucose-6-phosphatase, 5'-nucleotidase, acid phosphatase, and NADH- and NADPH-cytochrome C reductases), and cytochrome contents were determined. A stable, high salt-resistant attachment of some DNA with the nuclear membrane was observed as well as the association of some RNA with high salt-treated nuclear and rER membranes. The phospholipid pattern was identical for both nuclear and rER membranes and showed a predominance of lecithin (about 60%) and phosphatidyl ethanolamine (20-24%). Special care was necessary to minimize lipid degradation by phospholipases during isolations. Nonpolar lipids, mostly sterols and triglycerides, accounted for 35-45% of the membrane lipids. Sterol contents were relatively high in both membrane fractions (molar ratios of sterols to phospholipids ranged from 0.12 to 0.43). Sitosterol accounted for about 80% of the total sterols. Palmitic, oleic, and linoleic acids were the most prevalent acids in membrane-bound lipids as well as in storage lipids and occurred in similar proportions in phospholipids, triglycerides and free fatty acids of the membrane. About 80% of the fatty acids in membrane phospholipids and triglycerides were unsaturated. A cytochrome of the b5 type was characterized in these membranes, but P-450-like cytochromes could not be detected. Both NADH and NADPH-cytochrome c reductases were found in nuclear and rER membranes and appeared to be enriched in rER membranes. Among the phosphatases, Mg2+-ATPase and, to lesser extents, ADPase, IDPase and acid phosphatase activities occurred in the fractions, but significant amounts of monovalent ion-stimulated ATPase, 5'-nucleotidase and glucose-6-phosphatase activities did not. The results obtained emphasize that the close biochemical similarities noted between rER and nuclear membranes of animal cells extend to these fractions from plant cells.

Acid Phosphatase↗