Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This work was designed to determine possible effects of altered thyroid states on rates and sites of H 2 O 2 production by rat heart mitochondria. Rates of O 2 consumption and H 2 O 2 release, capacities to remove the peroxide, lipid peroxidation, cytochrome oxidase activities and ubiquinone levels were determined in heart mitochondria from euthyroid, hypothyroid, and hyperthyroid rats. Hypothyroidism decreased, whereas hyperthyroidism increased the rates of O 2 consumption and H 2 O 2 release during both state 4 and state 3 respiration with Complex I- or Complex II-linked substrates. The percentage of O 2 released as H 2 O 2 was not significantly affected by thyroid state. However, the mitochondrial capacity to remove H 2 O 2 increased in the transition from hypothyroid to hyperthyroid state, which indicates that H 2 O 2 production did not modify in proportion to the rate of O 2 consumption. The thyroid-state-linked changes in H 2 O 2 production were well correlated with the levels of hydroperoxides. Rates of H 2 O 2 release in the presence of respiratory inhibitors indicated that changes in the H 2 O 2 production occurred at both sites at which H 2 O 2 was generated in euthyroid state. This result and the observation that ubiquinol levels and cytochrome oxidase activities increase in the transition from hypothyroid to hyperthyroid state suggest that the modifications of H 2 O 2 production are due to a modulation by thyroid hormone of mitochondrial content of autoxidisable electron carriers.
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PMID:Effects of thyroid state on H2O2 production by rat heart mitochondria: sites of production with complex I- and complex II-linked substrates. 1266 72

We report the complete sequence of the mitochondrial genome of Penicillium marneffei, the first complete mitochondrial DNA sequence of a thermal dimorphic fungus. This 35 kb mitochondrial genome contains the genes encoding ATP synthase subunits 6, 8, and 9 (atp6, atp8, and atp9), cytochrome oxidase subunits I, II, and III (cox1, cox2, and cox3), apocytochrome b (cob), reduced nicotinamide adenine dinucleotide ubiquinone oxireductase subunits (nad1, nad2, nad3, nad4, nad4L, nad5, and nad6), ribosomal protein of the small ribosomal subunit (rps), 28 tRNAs, and small and large ribosomal RNAs. Analysis of gene contents, gene orders, and gene sequences revealed that the mitochondrial genome of P. marneffei is more closely related to those of molds than yeasts.
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PMID:The mitochondrial genome of the thermal dimorphic fungus Penicillium marneffei is more closely related to those of molds than yeasts. 1467 58

A phenolic antioxidant 3-tert-butyl-4-hydroxyanisole (BHA) is a widely used food additive. BHA had cytotoxicity in human monocytic leukemia U937 cells. BHA at 0.75 mM caused nuclear condensation and fragmentation, structural damage in mitochondria, decrease in mitochondrial transmembrane potential, and internucleosomal DNA cleavage. It induced the activities of caspase-3 and/or -7, -6, -8 and -9, especially high when DEVD-MCA was the substrate (caspase-3 and/or -7). DEVDase activity increased in time- and dose-dependent manner and high activity was observed in lysates of cells treated for 3 h at 0.75 mM. Addition of GSH (reduced glutathione) during the treatment of cells with BHA inhibited the induction of DEVDase activity, and the intracellular GSH level decreased as the concentration of BHA was raised. Intracellular ATP levels decreased in time- and dose-dependent manner when the cells were treated with BHA in the presence or absence of glucose. Enzyme activities involved in the respiratory chain were assayed with the mitochondrial fraction prepared from U937 cells. BHA distinctly inhibited NADH-ubiquinone oxidoreductase (complex I) and cytochrome c oxidase (complex IV) at low concentrations. Succinate-ubiquinone oxidoreductase (complex II) was also inhibited, but to somewhat less extent. Without mitochondrial enzymes, BHA stimulated the ubiquinol-dependent reduction of cytochrome c (complex III), but it might have some detrimental effects on the mitochondrial enzyme reaction of complex III. The inhibition of mitochondrial oxidative phosphorylation might corroborate the mechanistic evidence for apoptosis of leukemia cells by BHA. Cell death induced by BHA is primarily ascribable to apoptosis.
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PMID:Molecular mechanism of cell death induced by the antioxidant tert-butylhydroxyanisole in human monocytic leukemia U937 cells. 1499 91

Euglena gracilis cells grown under aerobic and anaerobic conditions were compared for their whole cell rhodoquinone and ubiquinone content and for major protein spots contained in isolated mitochondria as assayed by two-dimensional gel electrophoresis and mass spectrometry sequencing. Anaerobically grown cells had higher rhodoquinone levels than aerobically grown cells in agreement with earlier findings indicating the need for fumarate reductase activity in anaerobic wax ester fermentation in Euglena. Microsequencing revealed components of complex III and complex IV of the respiratory chain and the E1beta subunit of pyruvate dehydrogenase to be present in mitochondria of aerobically grown cells but lacking in mitochondria from anaerobically grown cells. No proteins were identified as specific to mitochondria from anaerobically grown cells. cDNAs for the E1alpha, E2, and E3 subunits of mitochondrial pyruvate dehydrogenase were cloned and shown to be differentially expressed under aerobic and anaerobic conditions. Their expression patterns differed from that of mitochondrial pyruvate:NADP(+) oxidoreductase, the N-terminal domain of which is pyruvate:ferredoxin oxidoreductase, an enzyme otherwise typical of hydrogenosomes, hydrogen-producing forms of mitochondria found among anaerobic protists. The Euglena mitochondrion is thus a long sought intermediate that unites biochemical properties of aerobic and anaerobic mitochondria and hydrogenosomes because it contains both pyruvate:ferredoxin oxidoreductase and rhodoquinone typical of hydrogenosomes and anaerobic mitochondria as well as pyruvate dehydrogenase and ubiquinone typical of aerobic mitochondria. Our data show that under aerobic conditions Euglena mitochondria are prepared for anaerobic function and furthermore suggest that the ancestor of mitochondria was a facultative anaerobe, segments of whose physiology have been preserved in the Euglena lineage.
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PMID:Euglena gracilis rhodoquinone:ubiquinone ratio and mitochondrial proteome differ under aerobic and anaerobic conditions. 1501 69

Thiosulphate is one of the products of the initial step of the elemental sulphur oxidation pathway in the thermoacidophilic archaeon Acidianus ambivalens. A novel thiosulphate:quinone oxidoreductase (TQO) activity was found in the membrane extracts of aerobically grown cells of this organism. The enzyme was purified 21-fold from the solubilized membrane fraction. The TQO oxidized thiosulphate with tetrathionate as product and ferricyanide or decyl ubiquinone (DQ) as electron acceptors. The maximum specific activity with ferricyanide was 73.4 U (mg protein)(-1) at 92 degrees C and pH 6, with DQ it was 397 mU (mg protein)(-1) at 80 degrees C. The Km values were 2.6 mM for thiosulphate (k(cat) = 167 s(-1)), 3.4 mM for ferricyanide and 5.87 micro M for DQ. The enzymic activity was inhibited by sulphite (Ki = 5 micro M), metabisulphite, dithionite and TritonX-100, but not by sulphate or tetrathionate. A mixture of caldariella quinone, sulfolobus quinone and menaquinone was non-covalently bound to the protein. No other cofactors were detected. Oxygen consumption was measured in membrane fractions upon thiosulphate addition, thus linking thiosulphate oxidation to dioxygen reduction, in what constitutes a novel activity among Archaea. The holoenzyme was composed of two subunits of apparent molecular masses of 28 and 16 kDa. The larger subunit appeared to be glycosylated and was identical to DoxA, and the smaller was identical to DoxD. Both subunits had been described previously as a part of the terminal quinol:oxygen oxidoreductase complex (cytochrome aa3).
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PMID:Coupling of the pathway of sulphur oxidation to dioxygen reduction: characterization of a novel membrane-bound thiosulphate:quinone oxidoreductase. 1530 18

The substantia nigra cells of a normal and Parkinson's disease human brain were obtained by the micropunch procedure and total RNA was isolated. Differential display RT-PCR of the total RNA revealed differentially expressed cDNAs that were identified by sequencing. This resulted in the identification of a panel of known and unknown differentially expressed genes. Complex I (NADH ubiquinone oxidoreductase) and Complex IV (cytochrome oxidase) whose expressions are decreased in Parkinson's disease were reduced in the Parkinson brain. Of the various differentially expressed genes, flotillin-1, also known as reggie-2, was of great interest to us. It is a relatively new protein which is an integral membrane component of lipid rafts and has been implicated in signal transduction pathway events. In situ hybridization histochemical studies with human and rat brain sections revealed the presence of this mRNA in discrete neuronal (and possibly glial) cells of the substantia nigra, locus coeruleus, cortex, hippocampus, hypothalamus, thalamus, motor nuclei, nucleus basalis, raphe nucleus, and other brain regions. Immunohistochemical studies revealed that flotillin-1 is not present in all the regions where the message was found. In the rat brain, the most prominent observation was the revelation of all catecholamine cells (dopamine, norepinephrine, epinephrine) by the flotillin-1 antibody (1:100 dilution). At a more concentrated dilution (1:10) other neuronal cells (e.g., cortex, thalamus, hindbrain) were observed. At both dilutions dense dopaminergic fibers were observed in the rat caudate-putamen, nigrostriatal tract, and substantia nigra. It is significant that there is an increased gene expression of flotillin-1 in the Parkinson substantia nigra/ventral tegmental area. The role of flotillin in these cells is unclear although it is interesting that the reggie-2/flotillin-1 gene was upregulated during retinal axon regeneration in the goldfish visual pathway (Schulte et al., Development 124:577-87, 1997) which suggests that flotillin-1/reggie-2 might play a role in axonal growth from the remaining substantia nigra cells of the Parkinson brain.
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PMID:Flotillin-1 in the substantia nigra of the Parkinson brain and a predominant localization in catecholaminergic nerves in the rat brain. 1554 8

Recently, it has been reported that the cold-stress protein CSP 310, discovered in the cytoplasm of cold-resistant winter cereals, causes uncoupling of oxidative phosphorylation during cold stress. To understand how the uncoupling mechanism of CSP differs from that of cyanide-insensitive alternative oxidase and plant mitochondrial uncoupling protein, we determined the effect of respiratory-chain inhibition on winter wheat (Triticum aestivum L. cv. Zalarinka) mitochondria. Our data show a possible involvement of stress protein CSP 310 in mitochondrial electron transport in winter wheat. CSP 310 shunts electrons around the main cytochrome pathway of the mitochondrial respiratory chain, i.e. electron flow bypasses ubiquinone and complex III via CSP 310 to complex IV.
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PMID:Non-phosphorylating bypass of the plant mitochondrial respiratory chain by stress protein CSP 310. 1566 69

Mitochondria are central to the efficient provision of energy for eukaryotic cells. The oxidative-phosphorylation system of mitochondria consists of a series of five major membrane complexes: NADH-ubiquinone oxidoreductase (commonly known as complex I), succinate-ubiquinone oxidoreductase (complex II), ubiquinol-cytochrome c oxidoreductase (cytochrome bc1 complex or complex III), cytochrome c-O2 oxidoreductase (complex IV), and F1F0-ATP synthase (complex V). Several lines of evidence have recently suggested that complexes I and III-V might interact to form supercomplexes. However, because of their fragility, the structures of these supercomplexes are still unknown. A stable supercomplex consisting of complex I and dimeric complex III was purified from plant mitochondria. Structural characterization by single-particle EM indicates a specific type of interaction between monomeric complex I and dimeric complex III in a 1:1 ratio. We present a model for how complexes I and III are spatially organized within the I+III2 supercomplex.
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PMID:Structure of a mitochondrial supercomplex formed by respiratory-chain complexes I and III. 1571 2

We report here the complete nucleotide sequence of the 30.9-kb mitochondrial genome of the dermatophyte fungus Epidermophyton floccosum. All genes are encoded on the same DNA strand and include seven subunits of the reduced nicotinamide adenine dinucleotide ubiquinone oxireductase (nad1, nad2, nad3, nad4, nad4L, nad5, and nad6), three subunits of cytochrome oxidase (cox1, cox2, and cox3), apocytochrome b (cob), three subunits of ATP synthase (atp6, atp8, and atp9), the small and large ribosomal RNAs (rns and rnl), and 25 tRNAs. A ribosomal protein gene (rps5) is present as an intronic ORF in the large ribosomal subunit. The genes coding for cob and cox1 carry one intron and nad5 carries two introns with ORFs. The mtDNA of E. floccosum has the same gene order as Trichophyton rubrum mtDNA, with the exception of some tRNA genes. Maximum likelihood phylogenetic analysis confirms T. rubrum as a close relative of E. floccosum. This is the first complete mitochondrial sequence of a species of the order Onygenales. This sequence is available under GenBank accession number AY916130.
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PMID:The complete DNA sequence of the mitochondrial genome of the dermatophyte fungus Epidermophyton floccosum. 1645 Jan 11

Three strains (so36, so42T and wo26) representing a novel Gram-negative, obligately aerobic, bacteriochlorophyll a-containing species of the alpha-4 subgroup of the Proteobacteria were isolated from freshwater lakes using a high-throughput cultivation technique. The non-motile and slender rod-shaped cells formed orange-red-pigmented colonies. The main carotenoids were nostoxanthin and keto-nostoxanthin. According to the absorption spectrum, two different photosynthetic light-harvesting complexes, an LHI complex and a B800-830-type peripheral LHII complex, were present in the cells. The predominant fatty acids of strain so42T were hexadecenoic acid (16 : 1omega7c) and octadecenoic acid (18 : 1omega7c), whereas 17 : 1omega6c and 14 : 0 iso 2-OH were present in smaller amounts. The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, glycolipid and sphingoglycolipids. The major respiratory lipoquinone was ubiquinone-10, whereas ubiquinone-9 was present in smaller amounts. The three strains were cytochrome oxidase-negative and catalase-positive and formed alkaline and acid phosphatases. The strains grew chemoorganoheterotrophically in mineral media supplemented with various organic acids, amino acids or complex substrates such as peptone and yeast extract. The G+C content of the genomic DNA of strain so42T was 64.3 mol%. The three novel isolates contained the same 16S rRNA gene sequence. The 16S rRNA gene sequence similarity to the closest phylogenetic relative Sandaracinobacter sibiricus was only 92.8 %. Accordingly, the three strains represent a new genus and species, for which the name Sandarakinorhabdus limnophila gen. nov., sp. nov., is proposed, with strain so42T (=DSM 17366T = CECT 7086T) as the designated type strain.
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PMID:Sandarakinorhabdus limnophila gen. nov., sp. nov., a novel bacteriochlorophyll a-containing, obligately aerobic bacterium isolated from freshwater lakes. 1658 5


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