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)

A microsomal fraction, prepared from mouse skin, catalyzed the hydroxylation of benzpyrene and aniline and the deethylation of 7-ethoxycoumarin. Contamination of the preparation by cytochrome oxidase and cytochrome P-420 was determined by spectral analysis. The enzyme activities studied in mouse skin (Swiss-Webster CD-1) did not respond to topical application of 3-MC. Twenty-four hours after topical application of TCDD to mice, microsomes from skin had 50% greater benzpyrene hydroxylase and 7-ethoxycoumarin deethylase activity, and 4- to 8-fold greater activity of these enzymes was seen after 72 hr. Increases in cytochrome P-450 content of skin microsomes could be demonstrated 24 and 72 hr after topical TCDD treatment of mice. Cholate treatment (solubilization) of skin microsomes, followed by centrifugation, removed the contaminating cytochrome oxidase. Quantitative and qualitative analyses of cytochrome P-450 difference spectra were made from the solubilized preparations.
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PMID:Cytochrome P-450 content and mixed-function oxidase activity in microsomes isolated from mouse skin. 1 Jan 43

An improved procedure for the preparation of cobalt-cytochrome c has been developed. Various factors influencing the cobalt insertion process are discussed. The optical spectra of cobalt-cytochrome c suggest a six-coordinated species. The spectral shifts occurring with oxidation-reduction are compared with those observed for deoxy-cobaltohemoglobin and ferrocytochrome c and attributed to the effect of d(z2) electron on stereoelectronic interactions between the axial ligands and the porphyrin pi systems. Cobalt-cytochrome c has Em,7 = -140 +/- 20 mV as compared to an Em,7 of +250mV for ferrocytochrome c. An explanation for this negative Em,7 is offered. Cobaltocytochrome c is oxidized by cytochrome oxidase at about 45% of the rate for native cytochrome c. On the other hand cobalticytochrome c was not reduced by microsomal NADH or NADPH cytochrome c reductase nor by mitochondrial NADH or succinate cytochrome c reductase. It appears that the integrity of the reductase binding site is destroyed and the oxidase binding site has been modified by cobalt substitution.
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PMID:Cobalt-cytochrome c. I. Preparation, properties, and enzymic activity. 16 80

1. A test system was developed to allow the measurement of protein synthesis in vitro in mitochondria from tissues which were accessible only in small quantities. The subcellular fractions which could be isolated are not purely mitochondrial but contain other particles as well, mainly microsomal, which are also active in protein synthesis. The following differences between mitochondrial and microsomal protein synthesis in vitro were used to measure selectively the mitochondrial portion in cell fractions sedimenting between 600 and 10000 X g: selective inhibition of mitochondrial protein synthesis by chloramphenicol/thiamphenicol selective inhibition of microsomal protein synthesis by cycloheximide kinetics of amino acid incorporation a medium favoring mitochondrial protein synthesis Activity of mitochondrial protein synthesis was based on measurements of cytochrome oxidase, a mitochondrial marker enzyme. 2. The technique developed was used for the evaluation of mitochondrial protein synthesis in mammalian embryonic tissues. It may equally well be applied to other tissues available in small amounts and in cases where the isolation of highly purified mitochondrial fractions is met with difficulty. 3. Comparing the rate of 14C-phenylalanine incorporation into mitochondrial protein from rat embryos at different stages of gestation, it was found that mitochondria from 11=day-old rat embryos exhibit an approximately 30-fold higher capacity for protein synthesis than those of day 13-16. On day 12 the capacity is 6 times higher than on the following days.
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PMID:Chloramphenicol/thiamphenicol and cycloheximide as tools for the measurement of mitochondrial protein synthesis in vitro during organogenesis of rat embryos. 17 91

The activities of various enzymes in some subcellular organelle fractions were examined after fixation in glutaraldehyde of various concentrations. A high speed centrifuge was used to shorten the fixation time. At the lowest concentration (0.01%) glutaraldehyde stabilized instable configurational states of mitochondria as revealed by electron microscopy. In addition, at this concentration, at least 70% of the original monoamine oxidase, ATPase and cytochrome oxidase activities were preserved. The activity of acid phosphatase, on the other hand, was enhanced in a lysosomal fraction when fixed with the aldehyde at higher concentrations, e.g. 0.1% and 1.0%. It is possible that the aldehyde at higher concentrations has the same effects on the lysosomal membrane as freeze-thawing. Glucose-6-phosphatase activity was well-preserved in a microsomal fraction fixed with 0.01% glutaraldehyde but was decreased drastically when the concentration of the aldehyde was greater than 0.05%.
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PMID:Stabilization of configurational states and enzyme activities in subcellular fractions after fixation with extremely low concentrations of glutaraldehyde. 17 35

The alkaloid camptothecin uncouples the growth and adivision of chick embryo cells. At a moderate dose (0.5 microgram/ml) it inhibits the incorporation of thymidine but not of uridine and leucine and the cell protein content increases and reaches twice that of control after 4 days of treatment. Twelve hours after addition of the drug, the activities per cell of the mitochondrial enzymes poly A hydrolase (EC 3.1. 4.21), cytochrome c oxidase (EC 1.9.3.1), and succinate dehydrogenase (EC 1.3.99.1) are greater than that of the control and keep increasing for at least 96 H. The increase in the activities of the mitochondrial enzymes precede that of NADPH-cytochrome c reductase (EC 1.6.2.4) and cytidine triphosphatase (EC 3.6.1.15), which are microsomal and plasma membranes enzymes respectively. Actinomycin D (0.01 microgram/ml) also inhibits the multiplication of the chick cells and the synthesis of DNA. The protein content of the actinomycin D treated cells decreases to 70% of the control by day 2. Nevertheless, the activities of the mitochondrial enzymes increase over that of the control but to a smaller extent that with camptothecin. The activities of the enzymes of the other organelles are not stimulated. Camptothecin at a higher dose (5.0 microgram/ml) induces effects similar to those of actinomycin D.
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PMID:Protein content and enzyme levels of cultured chick embryo cells treated with camptothecin and actinomycin D. 20 Mar 15

Myocardial ischemia was produced for 2 hours by coronary ligation in 11 dogs pretreated with methylprednisolone (MP, 30 mg/kg). Myocardial blood flow (MBF) was measured with microspheres (15 micrometer) in each tissue sample used for enzymatic analysis. Homogenates of these tissue samples were separated by ultracentrifugation into lysosome-rich and microsomal fractions and were analyzed for N-acetyl-beta-glusosaminidase (NAGA), beta-glucuronidase (beta-gluc), rotenone-insensitive-NADH-cytochrome c reductase (RINCR), and cytochrome oxidase. The enzymatic data from centrifugal fractions were grouped according to MBF values for statistical analysis of inter-group effects of ischemia. Significant losses (P less than 0.001) of NAGA and beta-gluc were seen in all MP-treated lysosome-rich particulate fractions that were isolated from zones demonstrating MBF values less than 25% of control (L-ischemia). Similar significant losses (P less than 0.001) of RINCR were seen in microsomal fractions from L-ischemia zones. Samples with MBF values greater than 25% but less than 75% of control (M-ischemia) also demonstrated significant decreases of lysosomal and microsomal enzymatic activity in specific fractions. When the data of the above MP-treated group were compared with the untreated control group, no significant intergroup effects of treatment with MP were observed. In addition, enzymatic data (NAGA, RINCR) were normalized prior to performing linear regression analyses; percent loss of particulate enzymatic activity was plotted against percent decrease in MBF. The effects of 2 hours of ischemia on the above biochemical parameters were comparable between untreated and MP-treated groups. Finally, when myocardial samples were grouped according to similar levels of MBF, statistical analysis using the general linear models procedure revealed no beneficial effect of MP treatment on changes in lysosomal hydrolases, microsomal RINCR, or latency of lysosomes.
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PMID:Lack of effect of methylprednisolone on lysosomal and microsomal enzymes after two hours of well-defined canine myocardial ischemia. 21 3

A simple method for the isolation of rat liver cells is described. The cells are shown, by an isotope dilution method, to maintain a constant rate of protein synthesis for 8 h of incubation. Antibodies to purified rat liver cytochrome oxidase were raised in rabbits and used to investigate the labeling of cytochrome oxidase in isolated rat liver cells and in vivo. The data demonstrate the occurrence of a precursor of the subunits of cytochrome oxidase that are synthesized in the cytoplasm. 1. Dodecylsulfate gel electrophoresis of the immunoprecipitates from isolated rat liver cells that had been labeled with [35S]methionine for 1 h showed a single radioactive peak with a molecular weight of 50000. 2. Judged by the effects of cycloheximide and chloramphenicol the labeled protein is synthesized on cytoplasmic ribosomes. 3. After labeling for 1 h in vivo with [3H]leucine the labeled protein appears to be exclusively associated with the hepatic microsomal fraction. 4. Ouchterlony double-diffusion analysis demonstrated immunological relationship between the precipitates from microsomes and cytochrome oxidase. In addition to the precipitates derived from mitochondria and microsomes immunoprecipitates were also obtained from the cytosol in comparable amounts; these again were immunologically related. The occurrence of large amounts of precursor(s) (or degradation products) of cytochrome oxidase in rat liver fractions is interpreted in terms of a regulatory pool for amino acid homeostasis in the organism.
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PMID:Immunoprecipitation of a cytoplasmic precursor of rat-liver cytochrome oxidase. 21 2

Activities of delta amino levulinic synthetase (DALS), cytochrome oxidase (E. C. 1.9.3.1.), NADH cytochrome b5 reductase (NADH red.), NADPH cytochrome P450 reductase (NADPH red.), contents of cytochrome P450 (cyt. P450) and cytochrome b5 (cyt. b5), and levels of hemoglobin and hematocrit were studied in three groups of rats: a) malnourished, b) during recovery from malnutrition, and c) controls. During severe protein malnutrition blood levels of hemoglobin and hematocrit were found to be decreased as well as DALS's activity in homogenized bone marrow and liver. The activity of NADH red, and contents of cyt. P.450 and cyt. b5 in hepatic microsomes were also found significantly depressed. The microsomal activity of NADPH red. as well as mitochondrial cytochrome oxidase did not present significant changes, since values obtained in malnourished rats were similar to those found for the control group. While recovering from malnutrition, when rats were fed a casein based diet (10 NDpCalo/o) supplemented with Fe and Cu, the hepatic enzymatic activities, the cytochrome contents of P450 and b5, and hematocrit experienced a spectacular increase, reaching towards the end of the refeeding period values which could be compared to those found in the control group. Nevertheless, DALS' activity in homogenized bone marrow and hemoglobin levels remained low. Results are discussed in relation to depressed activities and contents of enzymes, coenzymes, metabolites and subtrates involved in the hemoglobin synthesis in the rat bone marrow, during recovery from malnutrition.
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PMID:[Activity of delta-aminolevulinic synthetase, cytochrome oxidase and levels of the mixed function oxidase system during experimental protein malnutrition. Response to re-alimentation]. 22 23

1. The distribution of 3 beta-hydroxy steroid dehydrogenase was examined in the subcellular fractions of granulosa cells collected from the ovary of the domestic fowl. 2. 3 beta-hydroxy steroid dehydrogenase activity was observed in the mitochondrial (4000g for 20min) and microsomal (105 000g for 120min) fractions. 3. Approximately three times more 3 beta-hydroxy steroid dehydrogenase activity was associated with the cytochrome oxidase activity (a mitochondrial marker enzyme) in anteovulatory-follicle granulosa cells than with that of the postovulatory follicle. 4. Comparison of the latent properties of mitochondrial 3 beta-hydroxy steroid dehydrogenase with those of cytochrome oxidase and isocitrate dehydrogenase indicated that 3 beta-hydroxy steroid dehydrogenase is located extramitochondrially. 5. This apparent distribution of 3 beta-hydroxy steroid dehydrogenase is explained on the basis that the mitochondrial activity is either an artefact caused by a redistribution in the subcellular location of the enzyme, occurring during homogenization, or by the existence of a functionally heterogeneous endoplasmic reticulum that yields particles of widely differing sedimentation properties.
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PMID:Subcellular distribution of delta 5-3 beta-hydroxy steroid dehydrogenase in the granulosa cells of the domestic fowl (Gallus domesticus). 51 48

1. Low-temperature difference spectra of gradient-purified mitochondria of Acanthamoeba castellanii reveal the presence of cytochromes b-555, b-562 and c-549, with a-type cytochromes having a broad asymmetrical maximum at 602 nm; these components were also observed in specta of whole cells. 2. The a-type cytochromes are unusual in that they have split Soret absorption maxima (at 442 and 449 nm) and an uncharacteristic CO difference spectrum. 3. CO difference spectra of whole cells and 'microsomal' membranes show large amounts of cytochrome P-420 compared with cytochrome P-450. 4. Difference spectra in the presence of cyanide indicate the presence of an a-type cytochrome and two cyanide-reacting components, one of which may be cytochrome a3. 5. Whole-cell respiration in a N2/O2 (19:1) atmosphere was decreased by 50%, suggesting the presence of a low-affinity oxidase. This lowered respiration is inhibited by 50% by CO, and the inhibition is partially light-reversible; photochemical action spectra suggest that cytochrome a3 contributes to this release of inhibition. Other CO-reacting oxidases are also present. 6. The results are discussed with the view that cytochrome a3 is present in A. castellanii, but its identification in CO difference spectra is obscured by other component(s).
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PMID:The cytochromes of Acanthamoeba castellanii. 59 58


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