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)

The cells of Achromobacter parvulus, strain 1T, when grown in a methanol-containing medium, have two formate dehydrogenases, i.e. NAD-linked formate dehydrogenase and the formate dehydrogenase reducing the ferricyanide and tetrazolia. Only the latter enzyme was found in the cells grown in a medium with glycerol as a carbon source. These enzymes differ with respect to Km for formate and antigenic specificity. Km for formate oxidation by the cells of A. parvulus is lower than for formate of the NAD-dependent formate dehydrogenase and is equal to Km for the enzyme reducing artificial electron acceptors. The results obtained are discussed in terms of the existence of two cytochrome oxidase systems in the methylotrophic bacteria, differing in their sensitivities to the inhibition by formate.
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PMID:[Two ways of formate oxidation in methylotrophic bacteria]. 624 83

Low temperature (77 degrees K) absorption spectra of nonequilibrium states of cytochrome c oxidase produced by reduction of oxidases form protein by thermolysed electrons at 77 degrees K was studied. During reduction of cytochrome oxidase water-glycerol solution by thermolysed electrons at 77 degrees K a nonequilibrium reduced protein is formed. Low temperature (77 degrees K) absorption spectra of the nonequilibrium cytochrome oxidase differs from those reduced by ditionite. It was shown that the oxidation state of cytochrome a3 or addition of cytochrom c have no influence on these spectral changes. It is assumed, that the observed effects are conditioned by structural differences of reduced and oxidased cytochrome oxidase active center. Similar spectral changes were observed for cytochrome oxidase, bound to the mitochondrial membrane. At temperature increasing the low temperature reduced protein is relaxed to a corresponding equilibrium state. The spectral properties of bacterial cytochrome oxidase M. lysodeicticus do not depend on the way of reduction (by dytionite or thermolysed electrons at 77 degrees K).
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PMID:[Absorption spectra and magnetic circular dichroism of heme-containing proteins in nonequilibrium states. VI. Cytochrome c-oxidase]. 624 44

Isolated beef heart cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) contains four or five molecules of tightly bound diphosphatidylglycerol per monomer (2-heme complex). This lipid could be removed in part, or wholly, by mixing the enzyme with high concentrations of Triton X-100 and then centrifuging the mixture through a glycerol gradient equilibrated in the same detergent. Cytochrome c oxidase retaining three or more diphosphatidylglycerol molecules per monomer was fully active when assayed in 1-oleoyl lysophosphatidylcholine. Upon removal of one or more of these diphosphatidylglycerols, enzymic activity was lost. Full activation could be obtained by adding diphosphatidylglycerol to the assay mixture along with lysophosphatidylcholine but not by adding phosphatidylcholine or phosphatidylethanolamine. Direct binding experiments, kinetic studies, and previous work using arylazidocytochrome c derivatives [Bisson, R., Jacobs, B. & Capaldi, R. A. (1980) Biochemistry 10, 4173-4178], indicate that diphosphatidylglycerol is involved in binding of substrate cytochrome c to cytochrome c oxidase.
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PMID:Diphosphatidylglycerol is required for optimal activity of beef heart cytochrome c oxidase. 626 2

Cytochrome c-551 is a lipoprotein of about 10500 Da, found in thermophilic Bacillus PS3 grown under air-limited conditions. An expression vector was constructed from a structural gene of PS3 cytochrome c-551, synthetic oligonucleotide as a promoter for Bacillus stearothermophilus and a shuttle vector for Escherichia coli and B. stearothermophilus. The transformed cells of B. stearothermophilus K1041 expressed cytochrome c-551 as much as 5 nmol/mg membrane protein. The effects of over-expression on the host cells are analyzed; a slightly slower growth rate and an increased synthesis of cytochrome oxidase (about twofold) occurred. Over-expressed (4-10-fold) cytochrome c-551 were purified and its properties were examined to know whether the protein is processed as in PS3 cells grown under air-limited conditions. The molecular mass determination and treatment with Rhizopus lipase suggested that the same processes, cleavage of signal peptidase, blocking of the N-terminal group and acylation of glycerol residue by two fatty acids, took place in the over-expression system. Fatty acylation seems useful for the cytochrome c to be effectively oxidized.
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PMID:Over-expression of membrane-bound cytochrome c-551 from thermophilic Bacillus PS3 in Bacillus stearothermophilus K1041. 780 47

1. Cetaben in contrast to fibrates affect differently peroxisomal constituents. 2. Changes in large scale of liver non-peroxisomal parameters were compared after 10 days administration of equal doses (200 mg/kg/day) of cetaben and clofibric acid to male Wistar rats. 3. Clofibric acid treatment increased markedly the activities of FAD-glycerol-3-P dehydrogenase, beta-hydroxyacyl-CoA dehydrogenase, cytochrome-c oxidase, malic enzyme, NAD-glycerol-3-P dehydrogenase, ethoxycoumarin deethylase, p-nitroanisole demethylase and amounts of cytochrome P-450 and b5. 4. However no analogical changes were observed after cetaben treatment in the livers of experimental animals. 5. Both drugs increased the activities of alanine-glyoxylate aminotransferase-1 and acetylcarnitine transferase--enzymes with proven mitochondrial and peroxisomal location. 6. Cetaben contrary to clofibric acid does not increase solubilization of peroxisomal enzymes. 7. Enhanced acetylcarnitine transferase and alanine-glyoxylate aminotransferase-1 activities were distributed in mitochondria as well as in peroxisomes after clofibric acid treatment, however, only peroxisomes were enriched after cetaben administration. 8. The results obtained suggest that cetaben represents an exceptional type of peroxisome proliferator, specifically affecting peroxisomes, without having a negative influence on the processes of peroxisome biogenesis.
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PMID:Cetaben is an exceptional type of peroxisome proliferator. 800 53

Inner membranes were prepared from Escherichia coli strain RG 145, which is deficient in cytochrome bd, but overexpresses cytochrome bo [Au and Gennis (1987) J. Bacteriol. 169, 3237-3242]. The latter was purified 7-fold by extracting the membranes with octyl beta-D-glucopyranoside, followed by chromatography on DEAE-Sepharose, yielding 150 mg of protein/150 g wet weight of cells. Optical e.p.r. and low-temperature m.c.d. (magnetic circular dichroism) spectroscopies were used to investigate the nature of the protein ligands to the two haems in cytochrome bo from E. coli. Low-spin ferric haem b, the origin of a rhombic e.p.r. spectrum with g = 2.98, 2.26 and 1.50, gives rise to a charge-transfer band in the near-i.r. m.c.d. spectrum at 1622 nm. It is therefore concluded that haem b is co-ordinated by two histidine residues. The low-temperature m.c.d. spectrum of dithionite-reduced cytochrome bo comprises bands due both to low-spin ferrous haem b and to high-spin ferrous haem o. The bands arising from haem o show a direct correspondence with those in the m.c.d. spectrum of five-co-ordinate histidine-ligated ferrous haems such as myoglobin, implying that the protein residue liganding haem o is also histidine. This assignment was confirmed by measuring the e.p.r. spectrum of the nitric oxide derivative of fully reduced cytochrome bo. This showed a rhombic spectrum with g = 2.098, 2.008 and 1.987, and nuclear hyperfine splitting consistent with the co-ordination of ferrous haem by NO and histidine. The hyperfine splittings observed were 1.95 +/- 0.05 mT for the 14N of the NO ligand and 0.75 +/- 0.05 mT for the 14N of the proximal histidine. The e.p.r. spectrum of some samples of oxidized cytochrome bo show, at temperatures below 15 K, broad signals at g = 7.6, 3.6 and 2.8, and other preparations in the presence of glycerol yield signals at g = 10.8, 3.2 and 2.6. These signals, which are abolished by the addition of cyanide, are assigned to the binuclear centre, cytochrome o-CuB, suggesting that the binuclear site may display heterogeneity. Carbon monoxide reacts with the reduced enzyme with a stoichiometry of 1:1, and the dissociation constant for this reaction was determined to be 1.7 x 10(-6)M. The second-order rate constants for this reaction were measured and shown to be similar to those determined for bovine cytochrome aa3 [Gibson and Greenwood (1963) Biochem. J. 86, 541-554].
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PMID:Cytochrome bo from Escherichia coli: identification of haem ligands and reaction of the reduced enzyme with carbon monoxide. 838 47

We describe a new nuclear gene, CBT1 (Cytochrome B Termination), specifically involved in the generation of mature mRNA of cytochrome b in yeast mitochondria. Disruption of CBT1 (corresponding to ORF YKL 208W) results in a respiratory deficiency (no growth on acetate and ethanol, a reduced growth on glycerol, and a moderate growth on lactate). Cytochrome b is practically undetectable spectrally, while cytochromes a and a3 (cytochrome oxidase) appear unaffected by the disruption. Analysis of mitochondrial transcripts shows a reduced abundance of cytb mRNA, which in addition is approximately 200 nucleotides longer than that of the wild-type. Sequencing of the 3' region of the mutant cytb mRNA with an oligonucleotide primer positioned 148 nt downstream from the dodecamer sequence ("end-of-messenger" signal), demonstrates that the mutant transcript is extended beyond this position and is not processed at the conserved dodecamer cleavage site. The CBT1 gene product may be one of the components required for the exact 3' cleavage of the cytb messenger and may also be related to RNA splicing, since the intron-containing cytb gene is not as well expressed as the intron-less gene and the respiratory deficiency is more severe. We propose, that the CBT1 protein is necessary for the correct trimming of the end of cytb pre-mRNA and may be a part of the multi-component complex involved in this process.
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PMID:A novel nuclear gene, CBT1, essential for mitochondrial cytochrome b formation: terminal processing of mRNA and intron dependence. 933 40

Cardiolipin (CL) is a unique dimeric phospholipid localized primarily in the mitochondrial membrane. In eukaryotes, the enzyme CL synthase catalyses the synthesis of CL from two lipid substrates, CDP-diacylglycerol and phosphatidylglycerol. In earlier studies, we reported the purification of CL synthase from Saccharomyces cerevisiae and the cloning of the gene CRD1 (previously called CLS1) that encodes the enzyme. Because CL is an important component of the mitochondrial membrane, knowledge of its regulation will provide insight into the biogenesis of this organelle. To understand how CL synthesis is regulated, we analysed CRD1 expression by Northern blot analysis of RNA extracted from cells under a variety of growth conditions. CRD1 expression is regulated by mitochondrial development factors. CRD1 levels were 7- to 10-fold greater in stationary than in logarithmic growth phase, and threefold greater in wild-type than in rho 0 mutants. Expression was somewhat elevated during growth in glycerol/ethanol versus glucose media. In contrast, CRD1 expression was not regulated by the phospholipid precursors inositol and choline, and was not altered in the regulatory mutants ino2, ino4 and opi1. Mutations in cytochrome oxidase assembly, which led to reduced Crd1p enzyme activity, did not affect CRD1 expression. The crd1 null mutant makes a truncated CRD1 message. Although the null mutant can grow on both fermentable and non-fermentable carbon sources at lower temperatures, it cannot form colonies at 37 degrees C. In conclusion, CRD1 expression is controlled by factors affecting mitochondrial development, but not by the phospholipid precursors inositol and choline. Expression of CRD1 is essential for growth at elevated temperatures, suggesting that either CL or Crd1p is required for an essential cellular function.
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PMID:Cardiolipin synthase expression is essential for growth at elevated temperature and is regulated by factors affecting mitochondrial development. 998 37

Mitochondria constitute a source of reactive oxygen species. We tested whether mitochondrial function from human circulating lymphocytes is affected by smoking habit and if this could be associated with an increase in oxidative damage of biological membranes. We prospectively studied 35 smokers and 35 non-smoking healthy individuals matched by age and sex, with a similar physical activity. Individual enzyme activity of complexes II, III and IV of the mitochondrial respiratory chain (MRC) and of glycerol-3-phosphate dehydrogenase activity were measured spectrophotometrically. Intact cell respiration and oxidative rates after addition of pyruvate, succinate and glycerol-3-phosphate were assessed polarographically. Lipid peroxidation of biological membranes was assessed measuring the loss of cis-parinaric acid fluorescence. Results are expressed as means (+/-SD). Smokers showed a significant decrease in complex IV activity compared with non-smokers (112.8 +/- 40.9 versus 146.4 +/- 62.5 nmol/min/mg protein, respectively; 23% of inhibition; P = 0.01), while the rest of the complexes of MRC were unaffected. Conversely, oxidative rate with succinate, but not with the other substrates, was enhanced in smokers compared with non-smokers (16.7 +/- 10.4 versus 11.4 +/- 4.7 nmol oxygen/min/mg protein, respectively; 46% of activation; P = 0. 01). Lipid peroxidation of lymphocyte membranes was increased in smokers with respect to non-smokers (3.49 +/- 1.27 versus 4.39 +/- 1. 76 units of fluorescence/mg protein, respectively; 21% of increase; P = 0.03) and this increase correlated positively with succinate oxidation activation (R = 0.34, P = 0.02) and, to a lesser extent, with complex IV inhibition, although it did not reach statistical significance (R = 0.19, P = 0.18). In smokers, the MRC function of lymphocytes is disturbed and correlates with the degree of oxidative damage of membranes. This mitochondrial dysfunction could contribute to increased endogenous production of reactive oxygen species and could play a role in tobacco carcinogenicity.
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PMID:Smoking disturbs mitochondrial respiratory chain function and enhances lipid peroxidation on human circulating lymphocytes. 1038 8

Studies of respiration on glucose in procyclic Trypanosoma congolense in the presence of rotenone, antimycin, cyanide, salicylhydroxamic acid and malonate have indicated the presence of NADH dehydrogenase, cytochrome b-c1, cytochrome aa3, trypanosome alternate oxidase and NADH fumarate reductase/succinate dehydrogenase pathway that contributes electrons to coenzyme Q of the respiratory chain. The rotenone sensitive NADH dehydrogenase, the trypanosome alternate oxidase, and cytochrome aa3 accounted for 24.5 +/- 6.5, 36.2 +/- 4.2 and 54.1 +/- 5.5% respectively of the total respiration. Activities of lactate dehydrogenase, NAD(+)-linked malic enzyme and pyruvate kinase were less than 6 nanomoles/min/mg protein suggesting that they play a minor role in energy metabolism of the parasite. Phosphoenolpyruvate carboxykinase, pyruvate dehydrogenase, succinate dehydrogenase, NADP(+)-linked malic enzyme, NADH fumarate reductase, malate dehydrogenase, and alpha-ketoglutarate dehydrogenase and glycerol kinase on the other hand had specific activities greater than 60 nanomoles/min/mg protein. These enzyme activities could account for the production of pyruvate, acetate, succinate and glycerol. The results further show that the amount of glycerol produced was 35-48% of the combined total of pyruvate, acetate and succinate produced. It is apparent that some of the glycerol 3-phosphate produced in glycolysis in the presence of salicylhydroxamic acid is dephosphorylated to form glycerol while the rest is oxidised via cytochrome aa3 to form acetate, succinate and pyruvate.
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PMID:Pathways of glucose catabolism in procyclic Trypanosoma congolense. 1084 79


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