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)

Reactivity of mitochondria and peroxisomes to diaminobenzidine was investigated in Tetrahymena pyriformis and in wild-type and cytochrome oxidase-deficient Paramecium aurelia. Wild-type and cytochrome oxidase-deficient Paramecium gave positive mitochondrial reactions in the absence of added H2O2, and the deposits were enhanced by the addition of H2O2, whereas Tetrahymena gave positive mitochondrial reactions only upon addition of H2O2. These results are discussed in the light of the current ideas concerning the mechanism of staining by diaminobenzidine. Peroxisome-like organelles which react positively to diaminobenzidine, the reaction being partially inhibited by aminotriazole, were identified in both protozoa.
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PMID:Diaminobenzidine reactivity of mitochondria and peroxisomes in Tetrahymena and in wild-type and cytochrome oxidase-deficient Paramecium. 17 Mar 31

The ultrastructural localization of the activities of two enzyme systems in the culture forms of Leishmania donovani was shown by means of the diaminobenzidine techniques. The consistent deposition of electron dense reaction product of DAB oxidation without H2O2 in the kinetoplast and mitochondrial cristae and membranes was taken as evidence of the presence of cytochrome oxidase activity and cytochrome c. In the presence of H2O2, a more intense DAB oxidation was attributed to the activity of a peroxidase, possibly cytochrome c peroxidase. Mitochondrial and kinetoplast reactions to DAB were completely inhibited by KCN, methanol-nitroprusside, and by heating to 50 degrees C for 10 min. On the other hand, no inhibitory effect was observed with 100 mM 3-amino-1,2,4-triazole. Under all conditions of incubation tested, the microbodies were completely unreactive to DAB staining, which was utilized as the basis for their identification. These organelles are rounded, moderately electron-opaque bodies with a finely granular matrix and fine tubules or cores and are limited by a single membrane. Under normal staining method, the microbodies were indistinguishable from the rounded sections of mitochondria.
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PMID:Ultrastructural localization of diaminobenzidine reactivity in leishmania donovani promastigotes. 19 23

In pig lung tissue catalase positive particles (CPs) are abundant especially in type II pneumocytes and in Clara cells. In both cell types they occur as circular, oval or elongated membrane profiles surrounding a moderately electron dense matrix lacking a crystalline core. In Clara cells and in part of type II pneumocytes they are located as individual particles without any evident morphological relation to other cell organelles. In part of type II pneumocytes 5-8 particles are forming a group and their close relation to agranular endoplasmic reticulum cisterns is evident. The particles can be purified from lung homogenates by fractionated pelleting and subsequent rate sedimentation in a sucrose gradient using a zonal rotor. The catalase rich fraction bands in the middle of the gradient whereas cytochrome oxidase and part of the acid phosphatase sediments at its heavy end. A second part of acid phosphatase stays at the light end of the gradient and--according to morphological control--seems to correspond to lamellar bodies of the type II pneumocytes. The purified catalase positive particles do not contain hydroxyacid and D-aminoacid oxidases thought to be characteristic H2O2 producing enzymes of peroxisomal systems. The buoyant density of the particles (d = 1.195 g/cm3) is lower than that of liver peroxisomes. Cytochemical controls of the peroxisomal pellets exhibit the particles partly uniformly filled with reaction product, partly irregularly stained.
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PMID:Catalase positive particles from pig lung. Biochemical preparations and morphological studies. 21 Nov 1

Intracellular amastigotes of Leishmania donovani obtained from spleens of infected hamsters were studied by means of the diaminobenzidine technique for the presence of cytochromes and the activities of cytochrome oxidase and peroxidase. In the absence of H2O2, the oxidation of DAB, evidenced by electron-dense deposits localized on the cristae, inclusions, and enveloping membranes of the mitochondria and kinetoplast, revealed the activity of the cytochrome oxidase and the presence of the cytochromes. The increased deposition of DAB oxidation especially on the enveloping membranes in the presence of H2O2 suggests the activity of a peroxidase, probably cytochrome c peroxidase.
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PMID:Leishmania donovani: ultrastructural localization of diaminobenzidine reactivity in the amastigotes. 21 7

The matrix of some mitochondria in gastric parietal cells of rat and guinea pig evidenced affinity for the high iron diamine method which localizes sulfated complex carbohydrates selectively by light and electron microscopy. Such staining has not been observed elsewhere in the stomach. The high iron diamine reactive mitochondria about equaled in number those which were unreactive, and the two groups were indistinguishable morphologically. The distinction was not apparent either when mitochondria were stained by other cytochemical procedures including dialyzed iron for acidic complex carbohydrates, 3-3' diaminobenzidine-H2O2 at pH 6.0 for cytochrome oxidase, and Kominick's pyroantimonate osmium tetroxide for antimonate precipitable cations. The dialyzed iron method stained acid glycoconjugates in the outer intermembrane space in parietal cell mitochondria. These mitochondria stained more strongly with dialyzed iron than have any others examined heretofore with this method and comprised the only reactive mitochondria in the stomach. Parietal cell mitochondria also stained strongly for cytochrome oxidase but those of other gastric cells failed to evidence this reactivity.
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PMID:Cytochemical properties of mitochondria in the gastric parietal cell. 44 61

1. A polarographic assay of superoxide (O2--) dismutase (EC 1.15.1.1) activity is described, in which the ability of the enzyme to inhibit O2---dependent sulphite oxidation, initiated by xanthine oxidase activity, is measured. The assay was used in a study of the intracellular distribution of superoxide dismutase in rat liver. Both cyanide-sensitive cupro-zinc dismutase (92% of the total activity) and cyanide-insensitive mangano-dismutase (8%) were measured. 2. Rat liver homogenates contained both particulate (16%y and soluble (84%) dismutase activity. The particulate activity contained both types of dismutase, whereas nearly all the soluble dismutase was a cupro-zinc enzymes. The distribution pattern of mangano-dismutase was similar to that of cytochrome oxidase and glutamate dehydrogenase, indicating that the enzyme was probably present exclusively in the mitochondria. 3. Superoxide dismutase activity in the heavy-mitochondrial (M) fraction was latent and was activated severalfold and largely solubilized by sonication. Treatment of the M fraction with digitonin or a hypo-osmotic suspending medium indicated that most of the cupro-zinc dismutase was located in the mitochondrial intermembrane space, whereas the mangano-enzyme was located in the inner-membrane and matrix space. 4. A small amount of dismutase activity appeared to be present in the nuclei and microsomal fraction, but little or no activity in the lysosomes or peroxisomes. 5. The results are discussed in relation to the intracellular location of known O2---generating enzymes, the possible role of superoxide dismutase activity in intracellular H2O2 formation, and to current views on the physiological function of the enzyme.
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PMID:Polarographic assay and intracellular distribution of superoxide dismutase in rat liver. 81 Jan 38

Superoxide dismutase is shown to affect spectral changes observed upon cytochrome c oxidase reaction with H2O2, which indicates a possibility of O2- radicals being formed in the reaction. Using DMPO as a spin trap, generation of superoxide radicals from H2O2 in the presence of cytochrome oxidase is directly demonstrated. The process is inhibited by cyanide and is not observed with a heat-denatured enzyme pointing to a specific reaction in the oxygen-reducing centre of cytochrome c oxidase. The data support a hypothesis on a catalase cycle catalyzed by cytochrome c oxidase in the presence of excess H2O2 (Vygodina and Konstantinov (1988) Ann. NY Acad. Sci., 550, 124-138): (formula: see text)
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PMID:Cytochrome oxidase-catalyzed superoxide generation from hydrogen peroxide. 131 51

pH changes associated with the mitochondrial cytochrome oxidase reaction with H2O2 have been studied. In the presence of ferricyanide or Tris-phenanthroline complex of CoIII as electron acceptors, reaction of H2O2 with the oxidized cytochrome oxidase is accompanied by a steady proton release with a rate constant of ca. 3 M-1.s-1 at pH 6.8. The acidification is completely inhibited by superoxide dismutase and its pre-steady-state kinetics correlates with that of the oxoferryl compound (F) accumulation. Apparently, the proton release is linked to superoxide generation by cytochrome oxidase under these conditions. In the presence of superoxide dismutase and without the electron acceptors, the H2O2-induced transitions of cytochrome oxidase from the oxidized to the peroxy (P) and from the peroxy to the oxoferryl state are not associated with any significant proton release or uptake. The results point to the following mechanism of O2- generation and protonation states of the cytochrome oxidase compounds P and F: [formula: see text]
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PMID:pH changes associated with cytochrome c oxidase reaction with H2O2. Protonation state of the peroxy and oxoferryl intermediates. 133 Jun 83

Bovine heart submitochondrial particles (SMP) were exposed to continuous fluxes of hydroxyl radical (.OH) alone, superoxide anion radical (O2-) alone, or mixtures of .OH and O2-, by gamma radiolysis in the presence of 100% N2O (.OH exposure), 100% O2 + formate (O2- exposure), or 100% O2 alone (.OH + O2- exposure). Hydrogen peroxide effects were studied by addition of pure H2O2. NADH dehydrogenase, NADH oxidase, succinate dehydrogenase, succinate oxidase, and ATPase activities (Vmax) were rapidly inactivated by .OH (10% inactivation at 15-40 nmol of .OH/mg of SMP protein, 50-90% inactivation at 600 nmol of .OH/mg of SMP protein) and by .OH + O2- (10% inactivation at 20-80 nmol of .OH + O2-/mg of SMP protein, 45-75% inactivation at 600 nmol of .OH + O2-/mg of SMP protein). Importantly, O2- was a highly efficient inactivator of NADH dehydrogenase, NADH oxidase, and ATPase (10% inactivation at 20-50 nmol of O2-/mg of SMP protein, 40% inactivation at 600 nmol of O2-/mg of SMP protein), a mildly efficient inactivator of succinate dehydrogenase (10% inactivation at 150 nmol of O2-/mg of SMP protein, 30% inactivation at 600 nmol of O2-/mg of SMP protein), and a poor inactivator of succinate oxidase (less than 10% inactivation at 600 nmol of O2-/mg of SMP protein). H2O2 partially inactivated NADH dehydrogenase, NADH oxidase, and cytochrome oxidase, but even 10% loss of these activities required at least 500-600 nmol of H2O2/mg of SMP protein. Cytochrome oxidase activity (oxygen consumption supported by ascorbate + N,N,N',N'-tetramethyl-p-phenylenediamine) was remarkably resistant to oxidative inactivation, with less than 20% loss of activity evident even at .OH, O2-, OH + O2-, or H2O2 concentrations of 600 nmol/mg of SMP protein. Cytochrome c oxidase activity, however (oxidation of, added, ferrocytochrome c), exhibited more than a 40% inactivation at 600 nmol of .OH/mg of SMP protein. The .OH-dependent inactivations reported above were largely inhibitable by the .OH scavenger mannitol. In contrast, the O2(-)-dependent inactivations were inhibited by active superoxide dismutase, but not by denatured superoxide dismutase or catalase. Membrane lipid peroxidation was evident with .OH exposure but could be prevented by various lipid-soluble antioxidants which did not protect enzymatic activities at all.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The oxidative inactivation of mitochondrial electron transport chain components and ATPase. 216 88

Hydrogen peroxide binding to ferric cytochrome c oxidase in proteoliposomes brings about a red-shift of the enzyme Soret band and increased absorption in the visible range with two prominent peaks at approx. 570 and 607 nm. The molar absorptivity of the H2O2-induced difference spectrum is virtually pH-independent in the Soret band and at 570 nm, whereas the peak at 607 nm increases approx. 3-fold upon alkalinization in a narrow pH range 6.0-7.2, the effect being reversible. The pH profile of this transition indicates ionization of two acid-base groups with close pK values of 6.7. The lineshape of the peroxide compound difference spectrum is found to respond to pH changes inside the proteoliposomes. It is suggested that peroxide-complexed enzyme can undergo a pH-dependent transition to a form with increased extinction at 605-607 nm, possibly corresponding to the 420 nm (or 'pulsed') conformer of the ferric cytochrome oxidase formed as an early product of the enzyme oxidation. Accordingly, relaxation of the '420 nm' form to the resting state would be linked to an uptake of two protons from the M-aqueous phase. This protolytic reaction might be a partial step of the cytochrome oxidase proton pumping mechanism or it could serve to regulate interconversion between the active 'pulsed' and less active 'resting' states of the enzyme in the membrane.
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PMID:Effect of pH on the spectrum of cytochrome c oxidase hydrogen peroxide complex. 253 52


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