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)

Cytochrome c has two stimulatory effects on respiration of mitochondria especially those from wounded potato tuber. In the first place a stimulation of succinate- and NADH-consuming, antimycin-A-sensitive respiration, which reaches a maximal value at low cytochrome c concentrations, has been found. In the second place, at higher concentrations of cytochrome c a stimulation of NADH-consuming respiration occurs, which is antimycin-A-resistant, but KCN-sensitive. This antimycin-A-resistant, NADH-consuming respiration is absent, when no cytochrome c is added to the reaction medium. It is insensitive to metal chelators, to which the antimycin-A-and KCN-resistant plant mitochondrial alternative oxidase is sensitive. By measurements of NADH-cytochrome c reductase activities a corresponding antimycin-A-resistant NADH-cytochrome c reductase has been found, which is insensitive to osmotic shock treatment. A localization of this antimycin-A-resistant electron transport with NADH as the electron donor in the outer mitochondrial membrane is likely. In the mitochondrial preparations cytochrome c might stimulate by acting as an electron-carrier between the outer membrane reductase and the inner membrane cytochrome oxidase. A big increase of the outer membrane mediated electron transport in the mitochondria has been observed after wounding of potato tuber tissue. The ability of the tissue to produce this electron transport pathway after wounding disappeared after prolonged storage of the tubers. A possible function of this electron transport pathway in fatty acid desaturation during the wound-reaction is suggested.
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PMID:Cytochrome c dependent, antimycin-A resistant respiration in mitochondria from potato tuber (Solanum tuberosum L.). Influence of wounding and storage time on outer membrane NADH-cytochrome-c-reductase. 17 74

Distribution of the activities of some mitochondrial enzymes after sucrose density gradient ultracentrifugation of cell homogenates of S. cerevisiae in the early and late exponential growth phases is studied. It is demonstrated that young yeast cells have a characteristic complex distribution of NADH oxidase (cyanide-sensitive), succinate:ferricyanide-oxidoreductase (or succinate:2,6-dichlorophenol indophenol-oxidoreductase), NADH:2,6-dichlorophenol indophenol-oxidoreductase and cytochrome oxidase activities in sucrose density gradient; the distribution patterns of these activities are different. All the above activities are detected in a single relatively narrow band in mature yeast cells. Similar results are obtained in the experiments with glucose or galactose as a carbon source in the yeast growth media. The Arrhenius plots for NADH oxidase (as well as for succinate:2,6-dichlorophenol indophenol-oxidoreductase) activity do not differ in the case of "light" and "heavy" mitochondrial structures characteristic of yeast cells in the early exponential growth phase. Nevertheless, "light" and "heavy" mitochondrial structures differ with respect of the arrangement of certain respiratory chain components in their membranes NADH-dehydrogenase and cytochrome oxidase). This conclusion is drawn from the results obtained in the study of the interaction of the two types of structures with Fe(CN)6(3-), a non-penetrating ion and the antiserum to yeast mitochondria.
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PMID:[Changes in mitochondrial heterogenicity during aerobic growth of Saccharomyces cerevisiae yeasts]. 17 14

Activities of succinate dehydrogenase, succinate- and NAD-H-cytochrome c--reductases, and cytochrome c--oxidase was compared in 1 g tissue homogenate and homogenate fractions made from 1 g brain tissue using various solutions. Fractionation resulted in the increased activities of NADH- and succinate cytochrome reductases, and in the loss of succinate dehydrogenase activity, cytochrome oxidase was less influenced. These phenomena are regarded as signs of the interrelation between mitochondria and other constituents of brain cell within homogenates. Maximal quantity of mitochondria isolated from homogenates is no more than 20% of all the mitochondrial homogenates (according enzyme data). The electronogram of the brain mitochondrial preparation isolated in the Krebs--Ringer solution without glucose pointed out to a high homogeneity of mitochondria in the residue.
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PMID:[Enzyme, electron microscopic and polarographic characteristics of isolated rat brain mitochondria. III. Quantitative assessment of their distribution in fractions of the homogenate]. 18 80

1. Cells of the hydrogen bacterium Alcaligenes eutrophus are broken by gentle lysis using lysozyme treatment in hypertonic sucrose followed by osmotic shock. By this method, 93% of the in vivo activity of the H2 oxidase is recovered and the ATPase remains particle bound. In contrast, cell disruption in a French pressure cell diminishes the in vivo activity of the H2 oxidase by 50% and solubilizes the bulk of the ATPase. 2. The bacterium contains a periplasmic cytochrome c with bands at 418, 521 and 550 nm (difference spectrum). In addition to cytochrome aa3, b-560, c-553 and o, low temperature difference spectra of membranes show the presence of two further cytochromes (shoulders at 551 and 553 nm). 3. The unsupplemented membrane fraction catalyses the oxidation of hydrogen, NADH, NADPH, succinate, formate and endogenous substrate (NAD linked) at rates 2--3-fold higher than membranes obtained from cells disrupted in a French pressure cell. With the exception of the H2 oxidase all oxidase activities in lysozyme membranes are sensitive to carbonylcyanide m-chlorophenylhydrazone (20-100% stimulation of oxygen uptake). 4. The cytoplasmic fraction contains a B-type cytochrome with absorption maxima at 436 and 560 nm, capable of combining with CO; it contains non-covalently bound protohaem. In alkaline solutions a spectral transition to the haemochrome type with bands at 423, 526 and 556 nm occurs. The addition of NADH to an aerobic suspension of this cytochrome elicits new absorption maxima at 418, 545 and 577 nm (difference spectrum), which are believed to represent an oxygenated form of the reduced cytochrome.
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PMID:Respiratory components and oxidase activities in Alcaligenes eutrophus. 18 46

Tridemorph (N-tridecyl-2,6-dimethylmorpholine) inhibits both the NADH-oxidase and the succinate-cytochrome c oxydoreductase system of non-phosphorylating electron transfer particles from beef heart. The concentration required for half-inhibition amounted to 3,4 muM and 24 muM respectively. Two different sites of action in the respiratory chain could be localized by means of difference spectroscopy and measurements of enzymic activities in various partial systems. The inhibition of the NADH-ubiquinone oxydoreductase activity as well as the suppression of the NADH-induced reduction of all cytochromes on the one hand and the insensitivity of the NADH-ferricyanide oxydoreductase system on the other argue in favour of a site of action similar to rotenone. The partial suppression of the succinate-induced reduction of cytochrome b with simultaneous complete inhibition of the reduction of the other cytochromes indicate an additional site of action analogous to antimycin A. Both inhibitory actions appeared instantaneously after the addition of tridemorph and were counteracted by serum albumin. Furthermore, tridemorph inhibited the oxydation of external ferrocytochrome c but not that of ascorbate/tetra-methyl-p-phenylene-diamine-HCI (TMPID) showing that it is not a true inhibitor of the cytochrome oxidase. The TMPD-induced bypass of the succinate oxidation was inhibited as well. The possible role of the inhibition of the main pathway of the respiratory chain for the fungicidal action of tridemorph is discussed.
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PMID:[The systemic fungicide tridermorph as an inhibitor of the respiratory chain of electron transfer particles from beef heart mitochondria]. 18 65

Purified beef heart cytochrome-c oxidase preparations derived by three different laboratories contain NADH-K3 Fe (CN)6, NADH-nitrobluetetrazolium, and NADPH-nitrobluetetrazolium reductases. This is true of preparations exhibiting heme aa3 to protein ratios considered indicative of an excellent purity. An apparent association of cytochrome-c oxidase and one or more of the contaminants persists through immunodiffusion and nondenaturing electrophoresis and, in addition, in one instance copurification of NADH-K3Fe(CN)6 reductase and cytochrome-c oxidase to a constant ratio of specific activities was demonstrated. Cytochrome-c oxidase can be freed of the contaminants by equilibration with an NAD+-affinity matrix. As aconcomitant of equilibration with the matrix, the KM of cytochrome-c oxidase for ferrocytochrome-c is invariably decreased. Rat constants at low ferrocytochrome-c concentrations are consistently enhanced in all oxidase preparations upon equilibration with the NAD+ matrix. However, the effects of such equilibrations on the extrapolated Vmax varies from one preparation to another. Polyacrylamide gel electrophoresis in SDS-urea systems establishes that each of the preparations contains a minimum of three contaminants, each of an apparent formula weight of greater than 40,000 Daltons. NADH-NBT reductase was found to have a formula weight of approximately 46,000 Daltons. Their properties establish that NADH-K3Fe(CN)6 and NADH-NBT reductases are separate proteins; the separate identity of NADPH-NBT reductase has not yet been determined.
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PMID:Evidence for the presence of di- and triphospho pyridine nucleotide dehydrogenase derivatives as consistent contaminants of purified beef heart cytochrome-c oxidase. 18 83

Cytoplasmic membranes of Bacillus subtilis, grown in complex medium containing glucose, were fractionated into three membrane subfractions [light band (1.155 - 1.158 g/cm3); medium band (1.181 - 1.183 g/cm3); heavy band (1.21 - 1.25 g/cm3)] by sucrose density gradient centrifugation. Among these subfractions, the light and medium bands consisted mainly of membranes but the heavy band consisted of an irregular arrangement or aggregate of small globular protein components of 5 - 8 nm in diameter. We named this H-protein. H-protein formed trilamellar unit membrane structure when combined with lipid. In pulse-labeling and pulse-chase experiments with radioactive leucine, it was found that H-protein consisted of the newest membrane protein synthesized in the cells and the label incorporated into H-protein was shifted into light and medium band of the membranes during the chase. Cytochromes were not found in H-protein. However, when H-protein was incubated with haem alpha and protohaem, these compounds were incorporated into the apoproteins of the cytochromes present in H-protein and form cytochromes a and b. Cytochromes were also formed in H-protein which were isolated from the cells grown in the presence of haemin (haemin-grown H protein). Succinate dehydrogenase activity was increased about 4-fold by combining H-protein or haemin-grown H protein with lipid. H-protein had no cytochrome oxidase activity; however, haemin-grown H protein was found to have some of the activity and this was increased about 4-fold by combining the protein with lipid. Haemin-grown H protein was also found to form succinate: cytochrome c oxidoreductase when combined with lipid and vitamin K2. On the other hand, succinate oxidase was required for the addition of lipid, vitamin K2 and cytochrome c. NADH oxidase was also found in haemin-grown H protein and was activated about 9-fold in constituted reaction systems. Vesicles formed by haemin-grown H protein and lipid, could accumulate alanine and proline by addition of NADH or reduced phenazine methosulfate. Alanine and proline was also accumulated into the vesicles when transport energy was supplied as a membrane potential introduced by K+-diffusion via valinomycin. These results would indicate that H-protein contains the apoprotein of cytochromes, and a carrier involved in the active transport of alanine and proline.
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PMID:Isolation and characterization of hydrophobic proteins (H proteins) in the membrane fraction of Bacillus subtilis. Involvement in membrane biosynthesis and the formation of biochemically active membrane vesicles by combining H proteins with lipid. 18 52

Wild type cells of the green alga Chlamydomonas reinhardtii can grow in the in the dark by taking up and respiring exogenously supplied acetate. Obligate photoautotrophic (dark dier, dk) mutants of this alga have been selected which grow at near wild type rates in the light, but rapidly die when transferred to darkness because of defects in mitochondrial structure and function. In crosses of the dk mutants to wild type, the majority of the mutants are inherited in a mendelian fashion, although two have been isolated which are inherited in a clearly nonmendelian fashion. Nine mendelian dk mutants have been analyzed in detail, and belong to eight different complementation groups representing eight gene loci. These mutants have been tentatively grouped into three classes on the basis of the pleiotropic nature of their phenotypic defects. Mutants in Class I have gross alterations in the ultrastructure of their mitochondrial inner membranes together with deficiencies in cytochrome oxidase and antimycin/rotenone-sensitive NADH-cytochrome c reductase activities. Mutants in Class II have a variety of less severe alterations in mitochondrial ultrastructure and deficiencies in cytochrome oxidase activity. Mutants in Class III have normal or near normal mitochondrial ultrastructure and reduced cytochrome oxidase activity. Eight of the nine mutants show corresponding reductions in cyanide-sensitive respiration.
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PMID:Nuclear mutations affecting mitochondrial structure and function in Chlamydomonas. 19 32

In 175 dogs myocardial infarction was produced by high ligation of descending branch of left coronary artery. At various intervals after the intervention (1, 3, 5, 10, 30, 180 days), the activities and levels of NAD, NADH, FAD, riboflavin, cytochrome C, myoglobin, some NAD-dependent Krebs cycle enzymes, and mitochondrial succinate dehydrogenase and cytochrome oxidase were determined in the infarcted zone. It was found that in the infarcted zone there occurred substantial disturbances of various links constituting the tissue oxidative chain, in the stages of substrate dehydrogenation, electron transport to oxygen molecule, and myocardial oxygen uptake. The greatest disturbances took place in the systems of NAD and NAD-dependent enzymes, whereas the succinate oxidation system sustained substantially lesser damage. The decrease inlevels of flavonoids, which was likewise observed, participated also in the mechanism inhibiting succinate dehydrogenase. The cytochrome system activity was limited by the level of cytochrome C, whose deep decrease persisted considerably long in the infarcted zone. A certain role in disturbances of oxidative processes may have been played by the decreased concentration of myoglobin, an important myocardial reservoir of oxygen.
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PMID:Some myocardial factors of biological oxidation in experimental myocardial infarction. 19 79

Isolated rat heart was perfused with Langendorff's retrograde perfusion method, while the oxygen consumption and the left ventricular pressure were monitored continually. The steady-state contents of metabolites in the cardiac tissue, freeze clamped under various work-load conditions, were determined and the concentrations of free cytosolic ADP and AMP were calculated from the near equilibrium in creatine phosphokinase and adenylate kinase reactions. Increasing respiratory rate with increasing load was accompanied by a fall in the cytosolic free [ATP]/[ADP][Pi] but little change in the mitochondrial free [NAD+]/[NADH]. The free energy of ATP hydrolysis was calculated from the concentrations of the adenine nucleotides and compared with the values computed from the measured turnover number for cytochrome c and redox state of the mitochondrial NAD couple according to a mathematical model. The agreement between the two values was good over a wide range of metabolic conditions, which provides further support for the proposed near-equilibrium model of mitochondrial respiration with control exerted at the cytochrome oxidase-oxygen reaction.
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PMID:Energy relationships between cytosolic metabolism and mitochondrial respiration in rat heart. 20 95


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