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)

In populations of cultured arterial endothelial and smooth muscle cells grown under the same conditions, we have measured the total activity per cell of 10 enzymes commonly used as "markers" for subcellular organelles: NADH: ferricyanide reductase, NADH:cytochrome c reductase (rotenone insensitive). NADPH:cytochrome c reductase, alpha-glucosidase, 5'-nucleotidase, alkaline phosphodiesterase I, cytochrome oxidase, monoamine oxidase, cathepsin D, and N-acetyl-beta-glucosaminidase. Significant differences between the cell types were found for 7 of the 10 enzymes tested. The total activity of 5'-nucleotidase in cultured smooth muscle cells was 17 times that of cultured endothelial cells. Comparison of the activities in the two cell types freshly collected and in culture showed that the difference in 5'-nucleotidase in cultured cells is due principally to loss of activity from endothelial cells, suggesting that this activity is regulated differently in the two cell types. In both cell types cathepsin D activity rose during culture.
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PMID:Enzyme activities in endothelial cells and smooth muscle cells from swine aorta. 22 46

Some mitochondrial enzymatic activities (succinate dehydrogenase, NADH cytochrome reductase, cytochrome oxidase) were studied in the gastrocnemius and soleus muscle of the rat. The modifications of the enzyme activity, induced by endurance training, were found to be functions of 1) daily work load and 2) total training time. The treatment with an effective dose of vasodilating substances (papaverine, nicergoline, dipyridamole, and bamethan) showed that 1) nicergoline, bamethan, and dipyridamole were differently able to shorten the time of appearance of the increase in the enzymatic activities; 2) however, long-term treatments with these drugs did not prove able to modify the plateau level of the enzymatic activity increase, for a given amount of endurance training; 3) the pharmacodynamic effect on enzymatic activities was in no way related to the vasodilating effect of these drugs, since the effect was not observed with papaverine. The transition from a given level of endurance training to a lower one led to a proportional decrease of the mitochondrial enzymatic activities, thus pointing out the relation between amount of training and enzymatic activity. The drugs studied were unable to modify the decrease of enzymatic activity induced by lower work load.
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PMID:Mitochondrial enzymatic adaptation of skeletal muscle to endurance training. 23 62

Between pH approximately 4 and 10 cobaltocytochrome c (Cocyt-c) gives an electron paramagnetic resonance (EPR) spectrum with g parallel = 2.035, g the perpendicular = 2.223, CoA PARALLEL = 61.4 G, CoA the perpendicular = 49.8 G, NA parallel = 15.3 G, and NA THE PERPENDICULAR = 12.5 G. Comparisons with the EPR spectra of deoxycobaltomyoglobin, deoxycobaltohemoglobin, and model compounds and together with other evidence showed cobaltocytochrome c to have Met-80 and His-18 as its axial ligands. The protons of these ligands are seen as resonances shifted by the ring-current field of the porphyrin in the 300-MHZ 1H nuclear magnetic resonance (NMR) spectra of cobalticytochrome c (Cocyt-c+). The methyl and gamma-methylene protons of Met-80 in this molecule occupy positions with respect to heme c which are somewhat different from those in ferrocytochrome c. The 1H NMR spectra also showed that the methyl groups of Leu-32, Ile-75, Thr-63, thioether bridges, and the porphyrin ring in the cobalt protein are in the same state as in native enzyme; the same is also true for Tyr-59, His-26, and His-33 and also possibly Tyr-67, Tyr-74, and Phe-82. Above pH 11, Cocyt-c is converted to a five-coordinated form having g parallel = 2.026, g the perpendicular = 2.325, CoA parallel = 80 G, CoA the perpendicular approximately 10 G, NA parallel = 17.5 G, and NA the perpendicular not resolved. Below pH 1.0 the EPR spectrum of Cocyt-c is also five-coordinated with g parallel = 2.014, g the perpendicular = 2.359, CoA parallel = 93.8 G, and CoA the perpendicular = 38.8 G. The axial ligands in the alkaline and the acidic forms of Cocyt-c are His-18 and Met-80, respectively. New prominent proton resonance peaks are observed in cobalt-cytochrome c which are either absent or weak in native cytochrome c. These are situated at 3.0, 1.7, and 1.44 ppm, attributable, respectively, to the epsilon-CH2, DELTA-CH2 + beta-CH2, and gamma-CH2 of lysyl residues in random-coil-peptides. From the areas of these peaks, it is estimated that one-two lysyl residues in Cocyt-c have been modified; four-five lysyl residues in Cocyt-c+ have been modified. These alterations of surface charged groups are probably responsible for the lowered reactivity of Cocyt-c with cytochrome oxidase and the lack of reactivity of Cocyt-c+ with several cytochrome reductase systems.
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PMID:Cobalt-cytochrome c. II. Magnetic resonance spectra and conformational transitions. 24 Mar 81

The site of Na+-dependent activation in the respiratory chain of the marine bacterium, Vibrio alginolyticus, was investigated. The respiratory chain system contained ubiquinones (Q), menaquinones (MK), cytochromes b(560), c(553), d(630), and o(560). The membrane-bound and partially purified NADH dehydrogenase was stimulated 2- to 3-fold by the addition of 0.2 M Na+ or K+ and no specific requirement for Na+ was observed in this reaction step. The cytochrome oxidase showed no requirement for monovalent cations. The respiratory activity (NADH oxidase) of the membrane was lost on removal of the quinones, and the reincorporation of authentic Q-10 or MK-4 restored the activity. The rate of MK-4 reduction by NADH (menaquinone reductase) as measured using MK-4 incorporated membrane was activated by Na+, but only slightly by K+. The apparent Ka for Na+ was 78 mM for both menaguinone reductase and NADH oxidase. The requirement for Na+ of menaquinone reductase was greatly reduced in the presence of 0.2 M K+. Ubiquinone reductase as measured by using Q-10 incorporated membrane was also activated more effectively by Na+ than by K+. These results strongly suggested that the site of Na+-dependent activation in the respiratory chain of marine V. alginolyticus was at the step of NADH; quinone oxidoreductase.
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PMID:NADH: quinone oxidoreductase as a site of Na+-dependent activation in the respiratory chain of marine Vibrio alginolyticus. 45 42

Homogenates of HTC cells have been fractionated by differential centrifugation (in four particulate fractions: N, M, L, P, and a supernatant S) or isopycnic banding in linear sucrose gradients. On this basis, the following subcellular organelles may be characterized: (i) Mitochondria, detected by cytochrome oxidase and succinodehydrogenase, are collected in the M and L fractions, and equilibrate, as a narrow band, at a median buoyant density of 1.18 g/cm3. (ii) Lysosomes, detected by the latent hydrolases beta-glycerophosphatase and N-acetyl-beta-glucosaminidase, are largely sedimented in the M and L fractions, and display a broad density distribution pattern with a median value of 1.17 g/cm3. This density is decreased or increased after cultivation of the cells in presence of Triton WR-1339 or Dextran 500, respectively. The behavior of cathepsin D is somewhat at variance with that of the two other hydrolases. (iii) Plasma membrane is tentatively detected by alkaline phosphodiesterase I. Largely recovered in the P fraction, this enzyme equilibrates at a median density close to that of the lysosomal hydrolases; the bulk of cholesterol and about half of the leucyl-2-naphthylamidase are closely associated with alkaline phosphodiesterase I; HTC cells do not contain typical 5'-nucleotidase. (iv) Catalase-bearing particles, of high buoyant density (1.22 g/cm3) are present, but 30-40% of the catalase is also found readily soluble. NADPH- and NADH: cytochrome c reductase, and RNA show more complex distributions. It is suggested that the former enzyme is associated with the endoplasmic reticulum; as in liver, NADH reductase activity is shared between the endoplasmic reticulum and the mitochondria; half of the RNA is associated with free ribosomes of polysomes. True glucose-6-phosphatase could not be detected.
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PMID:Analytical fractionation of cultured hepatoma cells (HTC cells). 56 43

The present work is a continuation of our studies on mitochondrial functions and enzyme activities after acute exhaustive swimming in liver and myocardium. In rat heart mitochondria the activities of SDH, cytochrome oxidase and ATPase (DNP-stimulated) increase after swimming and remain at that level until the end of the 22-hour rest period studied. The enzyme complexes--rotenone-sensitive NAD. H-cytochrome c-reductase and succinate-cytochrome c-reductase--decrease their activities in both experimental groups. The reduced activity of these two enzymes is determined by changes in this part of the respiratory chain which occur after the incorporation of DCPIP in the oxidation-reduction processes. The marker enzyme of the outer mitochondrial membranes--rotenone-insensitive NAD.H-cytochrome c-reductase--reveals unchanged activity after swimming and a 22-hour period of rest. The different changes in the activities of enzymes with different localization and organization in heart mitochondria are explained by disorganization of the inner membranes after exhaustive swimming, which could induce both activation of some enzymes and inhibition of others. The effect of certain factors during muscle exercise which could cause the established structural and functional changes in the mitochondria is discussed.
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PMID:Effect of single exhaustive swimming on mitochondrial enzyme activities in rat myocardium. 61 30

Rat liver endoplasmic reticulum has been separated into four ribosome-containing subfractions, two from rapidly sedimentation endoplasmic reticulum and two from the microsomes, by differential centrifugation and sucrose density centrifugation. Ribosomes from one of the rapidly sedimenting subfractions were extracted by Trion X-100 as a complex with cytochrome P-450, optimally at a detergent protein ratio of 2/1 (w/w). Upon extraction approximately 50% of the cytochrome P-450 in the membrane appeared complex-bound to ribosomes, and, maximally, 6-7 subunit molecules of the cytochrome were attached per ribosome. The specific concentration of cytochrome P-450 on these ribosomes was 2.5-times higher than in the parent membrane. Cytochrome b5, glucose-6-phosphatase, NADPH-cytochrome c reductase, NADH-ferricyanide reductase, cytochrome oxidase and phospholipids were present in small or trace amounts on the ribosomes in relation to cytochrome P-450. Ribosomes extracted from other subfractions contained much less bound cytochrome P-450. Phenobarbital treatment induced an increase in the cytochrome P-450 content that was different for the various subfractions. This increase could not be correlated with changes in the amounts of cytochrome-ribosome complexes released by detergent. We propose that cytochrome P-450 is part of a specific binding site in the membrane for a fraction of the ribosomes attached to the endoplasmic reticulum. The ribosomes may be anchored to cytochrome P-450 via nascent chain proteins.
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PMID:On the involvement of cytochrome P-450 in the binding of ribosomes to a subfraction of rat-liver rapidly sedimenting endoplasmic reticulum. 83 30

The study of the participation of metals in evolution of oxidation-reduction processes is subdivided into two periods. During the first of them, from 1897 to 1937, the significance of manganese, iron, titanium, molybdenum, vanadium and copper in most important processes of metabolism was discovered. The second period, from 1937 to 1977, was devoted to the study of the role of metals in individual representatives of oxidoreductases and their evolution during transition of organisms from anaerobiosis to aerobiosis. In this evolution of special importance were bimetallic enzymes, such as nitrogenase, some nitrate reductases and hydrogenases, carbon dioxide reductase, xanthine oxidase, cytochrome oxidase. Owing to their ability to accomplish conjugated oxidation-reduction reactions, these oxidoreductases were transitional to still more complicated polymetallic systems with whose participation the electron transfer chains in subcellular structures were formed.
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PMID:[Participation of polyvalent metals in the evolution of oxidoreductases]. 91 1

Human spermatozoa contain appreciable amounts of intracellular glutathione, which has a protective function against peroxidative degradation of spermatozoal polyunsaturated fatty acids by the NADPH-dependent glutathione peroxidase/reductase enzymatic system. The glutathione system provides a basic defense against peroxidative damage, without which the superoxide dismutase system would dominate. Since oxidative damage is said to include enzyme leakage and changes in metabolism, cytochrome oxidase and lactate dehydrogenase activities were used as indicators of the energy metabolism in unwashed and washed human spermatozoa during lipid peroxidation. Lipid peroxidation was induced by aerobic incubation of sperms in the presence of sodium ascorbate and ferrous sulphate. In addition, since NADPH concentrations influence the concentration of reduced glutathione, we studied glucose-6-phosphate dehydrogenase activity as an indicator of pentose phosphate shunt activity, the main source of NADPH. Microdensitometric measurements of the three enzymes were made by a Vickers M85a scanning microdensitometer. We found that the lipid peroxidation process greatly affects the 3 enzymatic activities examined and that seminal plasma protects against the extensive deleterious effects of lipid peroxidation.
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PMID:Cytophotometric assay of cytochrome oxidase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activities in human peroxidized spermatozoa. 133 42

Transcription factor nuclear respiratory factor 1 (NRF-1) was originally identified as an activator of the cytochrome c gene and subsequently found to stimulate transcription through specific sites in other nuclear genes whose products function in the mitochondria. These include subunits of the cytochrome oxidase and reductase complexes and a component of the mitochondrial DNA replication machinery. Here we establish that a functional recognition site for NRF-1 is present in the ATP synthase gamma-subunit gene extending the proposed respiratory role of NRF-1 to complex V. In addition, biologically active NRF-1 sites are found in genes encoding the eukaryotic translation initiation factor 2 alpha-subunit and tyrosine aminotransferase, both of which participate in the rate-limiting step of their respective pathways of protein biosynthesis and tyrosine catabolism. The recognition sites from each of these genes form identical complexes with NRF-1 as established by competition binding assays, methylation interference footprinting, and UV-induced DNA cross-linking. Cloned oligomers of each NRF-1 binding site also stimulate the activity of a truncated cytochrome c promoter in transfected cells. The NRF-1 binding activities for the various target sites copurified approximately 33,000-fold and resided in a single protein of 68 kDa. These observations further support a role for NRF-1 in the expression of nuclear respiratory genes and suggest it may help coordinate respiratory metabolism with other biosynthetic and degradative pathways.
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PMID:Nuclear respiratory factor 1 activation sites in genes encoding the gamma-subunit of ATP synthase, eukaryotic initiation factor 2 alpha, and tyrosine aminotransferase. Specific interaction of purified NRF-1 with multiple target genes. 134 57


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