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 an in vitro study with rat liver, ammonium meta vanadate (NH4VO3) was found to inhibit microsomal ketamine N-demethylation, lipid peroxidation, and hydrogen peroxide formation; to have no effects on 4-methylaminoantipyrine N-demethylation and on glucuronyltransferase I activity, and to enhance glucuronyltransferase II. Mitochondrial succinate dehydrogenase and cytochrome c reductase were inhibited but cytochrome oxidase activity was enhanced by ammonium vanadate. Ammonium meta vanadate increased malate dehydrogenase activity but had no effect on glutamate, lactate, glycerophosphate, isocitrate, glucose-6-phosphate, and 6-phosphogluconate dehydrogenases.
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PMID:Action of ammonium meta vanadate on hepatic enzymes in vitro. 660 35

The mitochondrial and microsomal cytochrome P-450 contents of C57B1/6 mouse testis have been measured using difference spectroscopy on stable enzyme preparations containing the ferrous-carbon monoxide complex. Results were obtained on control animals (52 +/- 3 days of age) and on animals injected subcutaneously with human choriogonadotropin (0.017 micrograms/g body weight 24 h prior to sacrifice). The high ratio of testicular mitochondrial cytochrome oxidase to P-450, which has previously precluded measurements of basal P-450 levels, was overcome by using N,N,N',N'-tetramethyl-p-phenylene diamine to bypass site II, in combination with antimycin A to prevent reverse electron flow. The basal levels of mitochondrial and microsomal P-450 in mouse testis were 37.9 +/- 3.5 and 28.9 +/- 1.6 pmol/mg protein, respectively. Following administration of a desensitizing dose of gonadotropin, the respective values were lowered to 19.9 +/- 1.4 and 19.6 +/- 2.1 pmol/mg protein in 24 h. This is the first report of a gonadotropin-mediated decrease in mitochondrial P-450 and thus demonstrates that desensitization leads to alterations in both microsomal and mitochondrial P-450 in mouse testis.
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PMID:Effects of human choriogonadotropin on mitochondrial and microsomal cytochrome P-450 levels in mouse testes. 683 68

An analytical procedure for the subcellular fractionation of rat brain cortex is presented; it consists of a two-step procedure involving a differential centrifugation using the five-fraction scheme and an isopycnic centrifugation in continuous sucrose gradients. All fractions obtained were analyzed for their content of various constituents, such as receptor binding, uptake, and several marker enzymes. Special attention was paid to the subcellular distribution of the serotonin S2 receptors; they were mainly recovered in the microsomal P fraction, but a significant amount was also associated with the mitochondrial (M and L) fractions. After equilibration in density gradients, serotonin S2 receptors revealed two peaks, which were similarly affected after treatment with amitriptyline and/or yohimbine. There is no evidence to suggest that serotonin S2 receptors are associated with nerve endings containing the neurotransmitter serotonin. Although three main profiles, a microsomal, a mitochondrial, and a mixed one, clearly appear from the differential centrifugation, subgroups of these main profiles were also found. For instance, the microsomal distribution patterns of serotonin S2 receptors and 5'-nucleotidase are very similar, but differ from that of UDP-galactosyltransferase. Similarly, the mitochondrial profiles of cytochrome oxidase and 5-HT (serotonin) uptake are different. An analytical approach for brain fractionation, when performed with appropriate measurements (cytochrome oxidase, amine uptake, 5'-nucleotidase, and receptor binding), is rapid and clearly differentiates pre- and postsynaptic constituents.
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PMID:Analytical subcellular fractionation of rat cortex: resolution of serotonergic nerve endings and receptors. 686 31

Monkeys (Macaca nemestrina) were divided into four groups, and each group was fed a particular diet. The variables in the diets were as follows: diet A, 0.3 mg cholesterol/kcal nutrient; diet B, 1.0 mg cholesterol/kcal nutrient; diet C, 0.3 mg cholesterol/kcal nutrient, ethanol (36% of calories); diet D, 1.0 mg cholesterol/kcal nutrient, ethanol (36% of calories). Monkeys on the diets containing ethanol developed fatty liver. Mitochondria from ethanol-fed animals demonstrated significant decreases in uncoupler-stimulated, state 3, and state 4 succinate oxidation activity; respiratory control ratio; and ATP content. Liver microsomes isolated from the ethanol-fed groups demonstrated increased ethanol oxidizing activity with either NADPH or H2O2 as cosubstrate. Aniline hydroxylase and aminopyrine-N-demethylase activities were also elevated in ethanol-fed animals. The alterations in these functional properties were related primarily to ethanol in the diets. Cholesterol, while being less of a perturbant than ethanol, did elicit a significant decrease in cytochrome oxidase activity of mitochondria and a small but statistically significant increase in microsomal-associated ethanol oxidation activity. It appeared to potentiate the effect of ethanol in lowering mitochondrial respiratory control and ATP concentrations.
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PMID:Effect of dietary ethanol and cholesterol on metabolic functions of hepatic mitochondria and microsomes from the monkey, Macaca nemestrina. 702 93

Monoamine oxidase (MAO) activity (substrate: tyramine) has been studied in rat intestinal wall mitochondrial fractions identified by monitoring succinate dehydrogenase and cytochrome oxidase activities. The MAO activity, which was not due to contamination with mitochondria, has been also found in nuclear and microsomal (+hyaloplasm) fractions. Deamination of tyramine, serotonin and dopamine by rat intestinal mitochondrial MOA obeyed the Michaelis--Mentern kinetics. The Vmax values were the highest for deamination of tyramine, the lowest--for norepinephrine. The lowest Km value was recorded in the systems with 2-phenylethylamine. Data on the inhibitory effect of low concentrations of deprenyl suggest that 50% of the total tyramine deaminating activity in rat intestinal mitochondria was due to presence of MAO type B. Low concentrations of chlorgyline inhibited the deamination of tyramine in these systems by 20-30% suggesting a possibility of presence in the rat intestinal mitochondria of a tyramine deaminating activity distinct from MAO type A. Pyrazidol or harmine, which are selective inhibitors of the MAO type A, caused only partial (30-40%) inhibition of MAO activity (substrate: tyramine) in rat intestinal mitochondria. Controlled heating experiments indicated higher thermostability of MAO type B (substrate: 2-phenylethylamine) as compared with MAO type A (substrate: serotonin) in rat intestinal mitochondria. The data obtained suggest that rat intestinal mitochondria, contrary to human intestinal mucosa (cf. ref. 2), contain about 50% of MAO type B, which is comparatively thermostable and does not resemble in this respect the MAO type B in many other biological sources.
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PMID:[Properties of intestinal monoamine oxidase in the rat]. 708 Apr 82

Protein degradation rates for liver subcellular and submitochondrial fractions from neonatal (8-day), weanling (25-day) and adult rats were estimated by the double-isotope method with NaH14CO3 and [3H] arginine as the radiolabelled precursors [Dice, Walker, Byrne & Cardiel (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 2093-2097]. Decreased protein degradation rates were found during post-natal development for homogenate, nuclear, mitochondrial, lysosomal and microsomal proteins. A decrease in degradation rates for the immunoisolated subunits of monoamine oxidase and pyruvate dehydrogenase was also observed in neonatal and weanling rats respectively. The results suggest coordinate degradation of the subunits of the multi-subunit enzyme pyruvate dehydrogenase. Pyruvate dehydrogenase has a faster rate of degradation in adult rat liver than does cytochrome oxidase. Data analysis suggests heterogeneity of protein degradation rates in the mitochondrial outer membrane and intermembrane space fractions at each developmental stage but not in the mitochondrial inner membrane or matrix fractions. Results obtained for protein degradation rates in adult rat liver by the method of Burgess, Walker & Mayer [(1978) Biochem. J. 176, 919-926] in general confirmed the results obtained for the adult rat liver by the above method. No evidence of a subunit-size relationship for protein degradation was found for proteins in any subcellular or submitochondrial fraction.
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PMID:Protein degradation in rat liver during post-natal development. 730 3

Studies of the subcellular localization of neuroreceptors in the rat brain have shown that most of them are associated with light and low density subcellular fractions. In two human brain areas, quite different subcellular distributions were observed. After fractionation by differential centrifugation of frontal cortex homogenates, benzodiazepine and serotonin 5-HT2 receptors were mainly found in the heavy mitochondrial (M) fraction, whereas mu-opiate and muscarinic cholinergic receptors were mainly concentrated in the microsomal (P) fraction. In human putamen, the presynaptic markers of dopaminergic nerve terminals (neurotensin receptors, dopamine uptake sites and amine vesicular transporter-binding sites), benzodiazepine receptors and serotonin uptake sites were recovered both in the high and low density fractions, whereas the muscarinic, opiate and, to a lesser extent, dopamine D2 receptors were mostly concentrated in the microsomal fraction. In the cerebral cortex, after isopycnic centrifugation in sucrose gradients, neuroreceptors were found in the high density fractions where the peaks of cytochrome oxidase and that of nerve endings, as identified by amine uptake and by means of electron microscopy were also found. A single peak of benzodiazepine receptors was observed in high density (1.15-1.17 g/ml) fractions suggesting that these receptors are much more concentrated in the nerve terminals or dendrites rather than in the dendritic spines or vesicles. The fact that muscarinic and opiate receptors were recovered in the P fraction with plasma membrane constituents and also in M and L fractions, which is confirmed by a bimodal distribution in sucrose gradient, suggests that they are localized in both the nerve terminals or dendrites and in the small vesicles or dendritic spines. In the putamen, much of the specific binding to uptake sites for dopamine and serotonin was recovered in the high density fractions, but the existence of another peak at a lower density indicates the presence of microsomal uptake sites. The results indicate that differential and isopycnic fractionation methods performed on human brain samples, make it possible to separate tissue fractions enriched in nerve endings, dendrites, dendritic spines, plasma membranes or vesicles.
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PMID:Subcellular distribution of receptor sites in human brain: differentiation between heavy and light structures of high and low density. 758

It has been reported that aortic homografts that have been cryopreserved before transplantation remain viable longer as an allograft than tissue stored at 4 degrees C in an antibiotic solution. In the present study, we tested the hypothesis that storage of cardiac valve tissue by cryopreservation or by antibiotic preservation may alter the metabolic status of the tissue. Initially, we collected aortic valves composed of cardiac tissue, aortic root, and valvular tissue from cadaver donors. These specimens were divided into three equal portions, and one portion was analyzed before storage while the other two parts were stored for 3 weeks at either 4 degrees C in an antibiotic solution or at -196 degrees C in liquid nitrogen. All specimens were examined with regard to the following parameters: tissue structure, tissue viability, cell proliferative capacity, metabolic function, and identification of cell-specific antigens. We found no significant alterations in the structure of any of the three tissue components after antibiotic preservation or cryopreservation; however, cell viability and cell number were decreased in all three groups. All tissue samples grew in culture before storage. When we compared activities of the following organellar marker enzymes--lysosomal acid lipase, plasma membrane 5' nucleotidase, mitochondrial cytochrome oxidase, and microsomal neutral alpha-glucosidase--we observed no major differences between tissues stored by either technique. In addition, we observed no loss of enzymic activity as a result of storage. Finally, when cell lines isolated from each tissue specimen were incubated with monoclonal antibodies against cell-specific antigens in an immunoperoxidase assay, all the cell cultures proved to be endothelial cells. These results suggest that although cardiac valve tissue stored by cryopreservation or by antibiotic preservation retained its normal structure and metabolic capabilities, both storage techniques produced significant decreases in cell numbers and viability. However, only endothelial cells from tissue stored by cryopreservation retained the capacity to proliferate in vitro. These findings have important implications for the function of aortic homografts transplanted after storage.
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PMID:Biochemical and cellular characterization of cardiac valve tissue after cryopreservation or antibiotic preservation. 766 4

Neurological dysfunction is a characteristic feature of acute porphyrias, unexplained until now. One of the possible explanations is a deficiency of heme in the central nervous system, caused by a block in porphyrin biosynthesis. To test this possibility, the content of brain mitochondrial cytochrome a3 was determined after intracerebroventricular administration of the protoporphyrinogen oxidase-inhibiting herbicide fomesafen. It was established in in vitro experiments that fomesafen is a potent inhibitor of brain mitochondrial protoporphyrinogen oxidase (PROTOOX). Addition of 10(-6) M fomesafen to incubation mixture decreased PROTOOX from 1.02 nmol/mg/h (controls) to 0.42 nmol/mg/h. 10(-5)M of fomesafen decreased this activity to 0.27 nmol/mg/h. In in vivo experiments, 5 microleters of fomesafen solution containing 0.2 M fomesafen/l was administered to male rats by intracerebroventricular injection. The content of brain mitochondrial cytochrome a3 was determined 72 hours later. A slight decrease of the a3 content was observed (control rats 0.25 nmol/mg protein, treated rats 0.22 nmol/mg). Brain cytochrome P450 activities were below detection limits in both control and treated groups. In a separate experiment, male ICR mice were fed 1000 ppm of the protoporphyrinogen oxidaseinhibiting herbicide oxadiazon in the diet for 10 days. Liver microsomal cytochrome P450 content was decreased and liver porphyrins increased. An increase of porphyrin content was also observed in the testes of oxadiazon-fed mice, but testicular cytochrome a3 content was unchanged. The results indicate that, contrary to liver microsomal cytochromes P450, the mitochondrial cytochromes are not susceptible to changes in heme biosynthesis.
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PMID:The effect of protoporphyrinogen oxidase inhibitors on microsomal and mitochondrial cytochromes. 865 63

Crude oil pollution at drilling sites located within or in close proximity to agricultural pasture lands poses serious health risks to cattle raised on these lands. To investigate the clinical and systemic biochemical effects, cattle (8/group) were administered single oral doses of Pembina Cardium crude oil (PCCO) at 16.7, 33.4, and 67.4 g/kg, or water (control group) at 80 g/kg. Cattle exposed to PCCO showed dose-dependent clinical effects. At the lowest dosage, PCCO caused transient and minimal clinical effects; however, high dosages caused varied clinical signs which included tremors, nystagmus, vomiting, and pulmonary distress. On posttreatment day 7 or 30, four cattle from each treatment group were sacrificed and biochemical parameters were assayed in liver, lungs, and kidney cortex. In cattle monitored on posttreatment day 7, the PCCO-treated groups showed marked alterations from the control group in hepatic cytochrome P-450 (P-450), and in aryl hydrocarbon hydroxylase (AHH) and 7-ethoxycoumarin-O-deethylase (ECOD) activities of these tissues. Administration of PCCO caused significant increases (> 100%) in hepatic P-450, but produced variable effects on AHH and ECOD activities in each tissue. The activity of AHH was increased in all tissues; however, the effect was highest in kidney cortex (> 5000%), followed by liver (> 500%) and lungs (> 250%). The activity of ECOD was altered in a differential manner. It was either increased markedly (>1300%) in kidney cortex or increased slightly (20-30%) in liver, but decreased (> 80%) in lungs. The activities of respiratory chain enzymes (succinate-cytochrome c reductase, NADH-cytochrome c reductase and cytochrome oxidase), or NADPH-cytochrome c reductase and glutathione transferase were not changed significantly in any tissues. The alterations in P-450, AHH, and ECOD observed on day 7 were markedly reversed in cattle examined on day 30 posttreatment, indicating a recovery from induced changes. Studies in vitro with hepatic microsomal preparations from day 7 posttreatment groups showed that increases in AHH and ECOD activity in PCCO-treated cattle were due to induction of new isoforms of P-450, as evidenced by (1) the appearance of a 448-nm spectral peak, and (2) differential inhibitory effects of metyrapone and 7,8-benzoflavone on AHH and ECOD activities.
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PMID:Biochemical effects of Pembina Cardium crude oil exposure in cattle. 885 67


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