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 22,704-bp circular mitochondrial DNA (mtDNA) of the chlamydomonad alga Chlorogonium elongatum was completely cloned and sequenced. The genome encodes seven proteins of the respiratory electron transport chain, subunit 1 of the cytochrome oxidase complex (cox1), apocytochrome b (cob), five subunits of the NADH dehydrogenase complex (nad1, nad2, nad4, nad5, and nad6), a set of three tRNAs (Q, W, M), and the large (LSU)- and small (SSU)-subunit ribosomal RNAs. Six group-I introns were found, two each in the cox1, cob, and nad5 genes. In each intron an open reading frame (ORF) related to maturases or endonucleases was identified. Both the LSU and the SSU rRNA genes are split into fragments intermingled with each other and with other genes. Although the average A + T content is 62.2%, GC-rich clusters were detected in intergenic regions, in variable domains of the rRNA genes, and in introns and intron-encoded ORFs. A comparison of the genome maps reveals that C. elongatum and Chlamydomonas eugametos mtDNAs are more closely related to one another than either is to Chlamydomonas reinhardtii mtDNA.
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PMID:The mitochondrial genome of Chlorogonium elongatum inferred from the complete sequence. 976 88

Chronic ethanol consumption (10 g per kg body weight) significantly decreased the rate of respiration, P/O ratio, and respiratory control ratio (RCR). The activities of NADH dehydrogenase and cytochrome oxidase were significantly decreased in submitochondrial particles by ethanol administration compared to control. No significant difference was observed in membrane potential of submitochondrial particles. Cytochrome b, c and aa3 content of mitochondria were significantly decreased by ethanol feeding. Ethanol-induced inhibition on rate of respiration, P/O ratio, and RCR was relieved to a great extent by the administration of the aqueous extract of Phyllanthus fraternus (100 mg dry powder of the plant per kg body weight) along with ethanol. The decrease in the content of cytochromes due to ethanol administration was revived partially by aqueous extract of P. fraternus.
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PMID:Protective effect of P. fraternus against ethanol-induced mitochondrial dysfunction. 989 34

The components involved in the respiratory system of the euryarcheon Halobacterium salinarum were investigated by spectroscopic and polarographic techniques. Previous results about the cytochrome composition could be verified. However, under low oxygen tension, the expression of a d-type cytochrome was detected. Membranes exerted an NADH- and succinatecytochrome-c oxidoreductase as well as an NADH and succinate oxidase activity. These activities could be blocked by the following inhibitors: 7-jodocarboxylic acid, giving evidence for the presence of a type II NADH dehydrogenase, antimycin A, and myxothiazol, indicating the presence of a complex III analog, and the typical succinate dehydrogenase (SDH) and terminal oxidase inhibitors. Complex I inhibitors like rotenone and annonine were inactive, clearly excluding the presence of a coupled NADH dehydrogenase. In addition, no [Fe-S] resonances in the region of the NADH dehydrogenase (NDH) clusters could be observed after NADH addition. One of the terminal oxidases could be shown to act as a cytochrome-c oxidase with a Km value of 37 microM and an activation energy of 23.7 kJ/mol. The relative molecular mass of the endogenous c-type cytochrome could be determined as 14.1 kD. The complex III analog could be enriched after detergent extraction with Triton X-100 and hydroxylapatite (HTP) chromatography. The partially purified complex contained a Rieske iron-sulfur cluster, b- and c-type cytochromes, and was catalytically active in the decylubiquinone-cytochrome-c oxidoreductase assay.
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PMID:Studies of the electron transport chain of the euryarcheon Halobacterium salinarum: indications for a type II NADH dehydrogenase and a complex III analog. 993 47

Nitric oxide interactions with iron are the most important biological reactions in which NO participates. Reversible binding to ferrous haem iron is responsible for the observed activation of guanylate cyclase and inhibition of cytochrome oxidase. Unlike carbon monoxide or oxygen, NO can also bind reversibly to ferric iron. The latter reaction is responsible for the inhibition of catalase by NO. NO reacts with the oxygen adduct of ferrous haem proteins (e.g. oxyhaemoglobin) to generate nitrate and ferric haem; this reaction is responsible for the majority of NO metabolism in the vasculature. NO can also interact with iron-sulphur enzymes (e.g. aconitase, NADH dehydrogenase). This review describes the underlying kinetics, thermodynamics, mechanisms and biological role of the interactions of NO with iron species (protein and non-protein bound). The possible significance of iron reactions with reactive NO metabolites, in particular peroxynitrite and nitroxyl anion, is also discussed.
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PMID:Nitric oxide and iron proteins. 1032 Jun 64

The effect of carbon tetrachloride administration on liver mitochondrial function and the protective effect of an aqueous extract of Phyllanthus fraternus were studied in rats. The following changes were observed in mitochondria due to the administration of carbon tetrachloride. 1) A decrease in the rate of respiration, respiratory control ratio and P/O ratio using glutamate and malate or succinate as substrates. 2) A decrease in the activities of NADH dehydrogenase (35%), succinate dehydrogenase (76%) and cytochrome c oxidase (51%). The rate of electron transfer through site I, site II and site III was studied independently and found to be significantly decreased. 3) A decrease in the content of cytochrome aa3 (34%). 4) A significant decrease in the levels of phospholipids particularly cardiolipin and a significant increase in the lipid peroxide level was observed. The carbon tetrachloride induced toxicity may be partly due to the lipid peroxidation and partly due to the effect on protein synthesis. Administration of rats with an aqueous extract of P. fraternus prior to carbon tetrachloride administration showed significant protection on the carbon tetrachloride induced mitochondrial dysfunction on all the parameters studied.
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PMID:Protective effect of Phyllanthus fraternus against carbon tetrachloride-induced mitochondrial dysfunction. 1037 5

In the present study, we have applied a novel strategy involving the postmortem measurement of the mitochondrial respiratory chain enzyme cytochrome-c oxidase (COX; complex IV) to identify regional changes in energy metabolism in the basal ganglia of chronic, medicated schizophrenics. COX activity was decreased in the caudate nucleus but increased in the putamen and nucleus accumbens. An increase in succinate dehydrogenase (complex II) was evident in the putamen and nucleus accumbens, but changes were not seen with NADH dehydrogenase (complex I). An analysis of interregional correlations in energy metabolism revealed several anomalies in the connections between the caudate and putamen and the globus pallidus in schizophrenics. Results provide strong evidence that changes in baseline energy metabolism in specific regions of the basal ganglia may exist in the disease. Based upon the high degree of input it receives from associative cortical areas, results suggest that a defect in the caudate may underlie certain aspects of cognitive decline in schizophrenics. In contrast, an increase in COX in the putamen, which receives extensive projections from the sensorimotor cortex, may reflect an effect of chronic neuroleptic treatment on motor function.
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PMID:Mitochondrial function is differentially altered in the basal ganglia of chronic schizophrenics. 1045 34

The phylogenetic relationships of the African lungfish (Protopterus dolloi) and the coelacanth (Latimeria chalumnae) with respect to tetrapods were analyzed using complete mitochondrial genome DNA sequences. A lungfish + coelancanth clade was favored by maximum parsimony (although this result is dependent on which transition:transversion weights are applied), and a lungfish + tetrapod clade was supported by neighbor-joining and maximum-likelihood analyses. These two hypotheses received the strongest statistical and bootstrap support to the exclusion of the third alternative, the coelacanth + tetrapod sister group relationship. All mitochondrial protein coding genes combined favor a lungfish + tetrapod grouping. We can confidently reject the hypothesis that the coelacanth is the closest living relative of tetrapods. When the complete mitochondrial sequence data were combined with nuclear 28S rRNA gene data, a lungfish + coelacanth clade was supported by maximum parsimony and maximum likelihood, but a lungfish + tetrapod clade was favored by neighbor-joining. The seeming conflicting results based on different data sets and phylogenetic methods were typically not statistically strongly supported based on Kishino-Hasegawa and Templeton tests, although they were often supported by strong bootstrap values. Differences in rate of evolution of the different mitochondrial genes (slowly evolving genes such as the cytochrome oxidase and tRNA genes favored a lungfish + coelacanth clade, whereas genes of relatively faster substitution rate, such as several NADH dehydrogenase genes, supported a lungfish + tetrapod grouping), as well as the rapid radiation of the lineages back in the Devonian, rather than base compositional biases among taxa seem to be directly responsible for the remaining uncertainty in accepting one of the two alternate hypotheses.
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PMID:Searching for the closest living relative(s) of tetrapods through evolutionary analyses of mitochondrial and nuclear data. 1076 78

3'-azido-3'-deoxythymidine (AZT) is given to pregnant women positive for the human immunodeficiency virus type 1 (HIV-1) to reduce maternal-fetal viral transmission. To explore fetal mitochondrial consequences of this exposure, pregnant Erythrocebus patas monkeys were given daily doses of 1.5 mg (21% of the human daily dose) and 6.0 mg (86% of the human daily dose) of AZT/kg body weight (bw), for the second half of gestation. At term, electron microscopy of fetal cardiac and skeletal muscle showed abnormal and disrupted sarcomeres with myofibrillar loss. Some abnormally shaped mitochondria with disrupted cristae were observed in skeletal muscle myocytes. Oxidative phosphorylation (OXPHOS) enzyme assays showed dose-dependent alterations. At the human-equivalent dose of AZT (6 mg of AZT/kg bw), there was an approximately 85% decrease in the specific activity of NADH dehydrogenase (complex I) and three- to sixfold increases in specific activities of succinate dehydrogenase (complex II) and cytochrome-c oxidase (complex IV). Furthermore, a dose-dependent depletion of mitochondrial DNA levels was observed in both tissues. The data demonstrate that transplacental AZT exposure causes cardiac and skeletal muscle mitochondrial myopathy in the patas monkey fetus.
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PMID:Fetal mitochondrial heart and skeletal muscle damage in Erythrocebus patas monkeys exposed in utero to 3'-azido-3'-deoxythymidine. 1079 74

We present an overview of the gene content and organization of the mitochondrial genome of Dictyostelium discoideum. The mitochondria genome consists of 55,564 bp with an A + T content of 72.6%. The identified genes include those for two ribosomal RNAs (rn1 and rns), 18 tRNAs, ten subunits of the NADH dehydrogenase complex (nad1, 2, 3, 4, 4L, 5, 6, 7, 9 and 11), apocytochrome b (cytb), three subunits of the cytochrome oxidase (cox1/2 and 3), four subunits of the ATP synthase complex (atp1, 6, 8 and 9), 15 ribosomal proteins, and five other ORFs, excluding intronic ORFs. Notable features of D. discoideum mtDNA include the following. (1) All genes are encoded on the same strand of the DNA and a universal genetic code is used. (2) The cox1 gene has no termination codon and is fused to the downstream cox2 gene. The 13 genes for ribosomal proteins and four ORF genes form a cluster 15.4 kb long with several gene overlaps. (3) The number of tRNAs encoded in the genome is not sufficient to support the synthesis of mitochondrial protein. (4) In total, five group I introns reside in rnl and cox1/2, and three of those in cox1/2 contain four free-standing ORFs. We compare the genome to other sequenced mitochondrial genomes, particularly that of Acanthamoeba castellanii.
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PMID:The mitochondrial DNA of Dictyostelium discoideum: complete sequence, gene content and genome organization. 1082 Nov 86

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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