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)

To better characterize the role of skeletal muscle in chronic heart failure we studied energetic charge, metabolites and enzyme activity in the energy production pathway. We selected 15 males with severe chronic heart failure (NYHA class III, stable clinical conditions and in normal nutritional status) and seven controls. Controls and patients were submitted to biopsy of the vastus lateralis muscle in resting and fasting conditions. Hormone profiles were also evaluated. Our results showed near normal ATP, ADP and AMP concentrations, but there were substantially more reductions in glycogen (46 +/- 5 vs 77 +/- 6 mumoles glycosidic units.g-1 fresh tissue) and creatine phosphate (5 +/- 1 vs 13 +/- 1 mumoles.g-1 fresh tissue) in patients than in controls. We also found a reduction in glycolytic activity (pyruvate kinase 1009 +/- 79 vs 1625 +/- 26 nmoles. min-1.mg protein-1), despite normal tricarboxylic acid cycle velocity, an increase in alanine amino-transferase (964 +/- 79 vs 425 +/- 34 nmoles. min-1.mg protein-1) and in aspartate aminotransferase (515 +/- 44 vs 291 +/- 56 nmoles.min-1.mg protein-1). An increase was also observed in total NADH cytochrome c reductase (128 +/- 14 vs 68 +/- 5 nmoles.min-1.mg protein-1), while cytochrome oxidase activity was normal. The cortisol/insulin ratio was slightly elevated (77 +/- 4 vs 32 +/- 12). In conclusion, normonutritive patients with severe heart failure show an imbalance in the energy production/utilization ratio. The impairment is probably due both to a decrease in production and an increase in consumption of energy owing to greater cellular workload and/or a hypercatabolic state.
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PMID:Biochemical analysis of muscle biopsy in overnight fasting patients with severe chronic heart failure. 892 17

The legume Vicia sativa (common vetch) harbors the neurotoxic nonprotein amino acid beta-cyano-L-alanine (BCLA) and its gamma-glutamyl derivative. BCLA elicits hyperexcitability, convulsions, and rigidity in chicks and rats after oral or intraperitoneal administration, but the mechanism of its action is unknown. The effect of different concentrations of BCLA (0.075-10.0 mM) has been investigated in an organotypic tissue culture system. BCLA concentrations of 0.075 and 0.60 mM had no effect, even up to 6 hr. No changes were observed in cultures treated with 1 mM BCLA for 4 hr. BCLA (2.0-10.0 mM) induces concentration-dependent changes in the explants. The explants display neurona vacuolation, chromatin, clumping, and dense shrunken cells, a pathological response generally seen with excitotoxin. MK-801 (35 microM), which blocks the open ion channel associated with the N-methyl-D-aspartate (NMDA) class of glutamate receptors, attenuates the neurotoxic property of BCLA, while the non-NMDA antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (10-20 microM), provides no significant protection. Treatment of isolated mouse brain mitochondria with up to 5 mM BCLA had no inhibitory effect on the activity of NADH dehydrogenase (complex I) or cytochrome or oxidase (complex IV), a cyanide-sensitive enzyme. These results suggest that the neurotoxicity of BCLA (or derivative) is mediated directly or indirectly through NMDA receptors.
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PMID:beta-Cyano-L-alanine toxicity: evidence for the involvement of an excitotoxic mechanism. 902 49

Transport of inorganic phosphate in Streptomyces granaticolor was characterized in two growth stages; kinetic parameters were determined and two transport systems were found in both stages, with the following values: KT1 = 0.06 mM, Jlim1 = 0.95 nmol min-1 (mg DS)-1, and KT2 = 1.80 mM, Jlim2 = 25 nmol min-1 (mg DS)-1. Both systems require metabolic energy and substrates, such as sugars or polyols; when alanine was used or the energy source was omitted, the kinetic parameters changed in both systems. Both systems were inhibited by the ionophore cccp with identical k(i). KCN, an inhibitor or terminal cytochrome oxidase, inhibited the uptake of phosphate only partially, the uptake was inhibited completely when also the inhibitor of the alternative oxidative pathway (salicylhydroxamic acid) was added. Antimycin A inhibited the uptake completely. Arsenate inhibited competitively.
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PMID:Characterization of phosphate transport in Streptomyces granaticolor. 909 Apr 50

We propose the name Pseudomonas monteilii for a new species of gram-negative, rod-shaped, motile bacteria that were nonhemolytic on blood agar and were isolated from clinical sources. The 10 strains of P. monteilii were incapable of liquefing gelatin. They grew at 10 degrees C but not at 41 degrees C, produced fluorescent pigments, catalase, and cytochrome oxidase, and possessed the arginine dihydrolase system. They were capable of respiratory but not fermentative metabolism. They did not hydrolyze esculin or starch and were able to use benzylamine, alpha-aminobutyrate, D-ribose, L-arabinose, butyrate, valerate, isovalerate, isobutyrate, inositol, phenylacetate, D-alanine, and amylamine. They possessed L-phenylalanine arylamidase, L-lysine arylamidase, L-alanine arylamidase, gamma-glutamyl-transferase, glycyl-phenylalanine arylamidase, L-tryptophan arylamidase, glycyl-L-alanine arylamidase, esterase C4, esterase C6, esterase C8, esterase C9, esterase C10, and esterase C18. DNA relatedness studies revealed that P. monteilii strains formed a homogeneous DNA hybridization group. A total of 57 strains representing previously described or partially characterized taxa belonging to the genus Pseudomonas were 6 to 54% related to P. monteilii. The highest hybridization values were obtained with strains belonging to or related to Pseudomonas putida biovar A. The average G+C content of the DNA was 60.5 +/- 0.5 mol% for four of the P. monteilii strains studied. The type strain of P. monteilii is CFML 90-60 (= CIP 104883); it was isolated from bronchial aspirate and has a G+C content of 60 mol%. The clinical significance of these organisms is not known.
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PMID:Pseudomonas monteilii sp. nov., isolated from clinical specimens. 922 17

Cytochrome c (cyt c) release was investigated in cerebellar granule cells used as an in vitro neuronal model of apoptosis. We have found that cyt c is released into the cytoplasm as an intact, functionally active protein, that this event occurs early, in the commitment phase of the apoptotic process, and that after accumulation, this protein is progressively degraded. Degradation, but not release, is fully blocked by benzyloxycarbonyl-Val-Ala-Asp-fluoromethylchetone (z-VAD-fmk). On the basis of previous findings obtained in the same neuronal population undergoing excitotoxic death, it is hypothesized that release of cyt c may be part of a cellular attempt to maintain production of ATP via cytochrome oxidase, which is reduced by cytosolic NADH in a cytochrome b5-soluble cyt c-mediated fashion.
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PMID:Early release and subsequent caspase-mediated degradation of cytochrome c in apoptotic cerebellar granule cells. 1048 78

Evidence is increasing that mitochondrial dysfunction is involved in amyotrophic lateral sclerosis, a neurodegenerative disease characterized by selective motoneuron death. To study the role of mitochondrial dysfunction in the pathways leading to motoneuron death, we developed an in vitro model of chronic motoneuron toxicity, based on malonate-induced inhibition of complex II in the mitochondrial electron transport chain. Treatment with malonate resulted in a dose-dependent decrease in cellular ATP levels. We observed that motoneurons were significantly more vulnerable to mitochondrial inhibition than control neurons in the dorsal horn. We could reproduce this dose-dependent phenomenon with the complex IV inhibitor sodium azide. The free radical scavenger alpha-phenyl-N-tert-butylnitrone, the AMPA/kainate receptor blocker 6-cyano-7-nitroquinoxaline-2,3-dione, and riluzole, a drug that is currently used for the treatment of amyotrophic lateral sclerosis, were protective against malonate-induced motoneuron death. Furthermore, the caspase inhibitors N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone and z-Asp-Glu-Val-Asp-fluoromethyl ketone were both protective against malonate toxicity. Our model shows that chronic mitochondrial inhibition leads to selective motoneuron death, which is most likely apoptotic.
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PMID:Chronic mitochondrial inhibition induces selective motoneuron death in vitro: a new model for amyotrophic lateral sclerosis. 1069 48

The heme-copper cytochrome oxidase of Escherichia coli (cytochrome bo(3)) was tagged with oligohistidine at the C-terminus of the small noncatalytic subunit IV. After detergent solubilization, the enzyme was purified by a one-step procedure with immobilized metal affinity chromatography. Using different cytochrome bo(3) constructs as reference, the products were investigated by mass spectroscopical and immunological methods. Several posttranslational modifications of subunits II, III, and IV were observed: (1) N-terminal methionines of subunits III and IV are split off. (2) Fifty percent of subunit III polypeptides are acetylated, presumably at the N-terminal alanine. (3) Lipoprotein processing of subunit II involves cleavage of the signal peptide. (4) Maturation of subunit II [Ma, J., Katsonouri, A., and Gennis, R. B. (1997) Biochemistry 36, 11298-11303] alters the structure of the N-terminal cysteine by N-palmitoylation and S-glyceryldipalmitoylation. (5) A hexapeptide is split off from the C-terminus of subunit II. This happens subsequently to the N-terminal lipoprotein processing step and is dependent on the growth state of cells.
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PMID:Multiple posttranslational modifications at distinct sites contribute to heterogeneity of the lipoprotein cytochrome bo(3). 1082 72

A search of the Bacillus subtilis genome identifies a potential homolog, ypmQ, of the inner mitochondrial membrane protein Sco1 from yeast. Sco1 has been found to aid the delivery of copper to cytochrome c oxidase. B. subtilis expresses two members of the cytochrome oxidase family, a cytochrome c oxidase that has two copper centers, Cu(A) and Cu(B), and a menaquinol oxidase that has only Cu(B). Deletion of ypmQ in B. subtilis depresses expression of cytochrome c oxidase but not menaquinol oxidase. Levels of cytochrome c oxidase recover when copper is added to the growth medium of the DeltaypmQ strain or when ypmQ is expressed from a plasmid. Neither treatment affects the amount or activity of menaquinol oxidase. YpmQ in which two conserved cysteines are replaced by serines and a conserved histidine is replaced by alanine do not complement the deletion of ypmQ even though these mutant forms are found in the membrane extract at a level similar to the wild type protein. We propose that the two cysteines and the histidine are critical for the function of YpmQ and suggest they are involved in copper exchange between YpmQ and the Cu(A) site of cytochrome c oxidase.
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PMID:Characterization of YpmQ, an accessory protein required for the expression of cytochrome c oxidase in Bacillus subtilis. 1083 75

Activities of succinate oxidase, fumarate reductase (FR) and succinate dehydrogenase (SDH) under a set of defined conditions were determined in the mitochondrial isolate from Setaria digitata, the filarial parasite from the cattle Bos indicus. Presence of only two activities namely SDH and succinate--UQ reductase of the succinate oxidase system could be detected in S. digitata. In the absence of cytochromes, the 3rd enzyme of the complex namely cytochrome oxidase is absent and it is proposed that an alternative oxidase is responsible for completing the succinate oxidation expressed as succinate oxidase activity. Though SDH and FR catalyse reverse reactions, they responded differently to modulators such as oxaloacetate, aspartate, alanine, pyruvate and fumarate. The degree of response of the two activities against inhibitors of electron transport was also different. Interestingly fumarate caused only 50% inhibition of succinate oxidation, while the effect against FR was more convincing.
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PMID:Succinate oxidase and fumarate reductase systems of filarial parasite Setaria digitata. 1098 24

Protons are transferred from the inner surface of cytochrome c oxidase to the active site by the D and K pathways, as well as from the D pathway to the outer surface by a largely undefined proton exit route. Alteration of the initial proton acceptor of the D pathway, D132, to alanine has previously been shown to greatly inhibit oxidase turnover and slow proton uptake into the D pathway. Here it is shown that the removal of subunit III restores a substantial rate of O(2) reduction to D132A. Presumably an alternative proton acceptor for the D pathway becomes active in the absence of subunit III and D132. Thus, in the absence of subunit III cytochrome oxidase shows greater flexibility in terms of proton entry into the D pathway. In the presence of DeltaPsi and DeltapH, turnover of the wild-type oxidase or D132A is slower in the absence of subunit III. Comparison of the turnover rates of subunit III-depleted wild-type oxidase to those of the zinc-inhibited wild-type oxidase containing subunit III, both reconstituted into vesicles, leads to the hypothesis that the absence of subunit III inhibits the ability of the normal proton exit pathway to take up protons from the outside in the presence of DeltaPsi and DeltapH. Thus, subunit III appears to affect the transfer of protons from both the inner and outer surfaces of cytochrome oxidase, perhaps accounting for the long-observed lower efficiency of proton pumping by the subunit III-depleted oxidase.
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PMID:A role for subunit III in proton uptake into the D pathway and a possible proton exit pathway in Rhodobacter sphaeroides cytochrome c oxidase. 1280 96


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