Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The rabbits being repeatedly poisoned with small doses of sodium cyanide, the activity of succinic dehydrogenase in the tissues does not essentially change. The activity of NAD.H2-cytochrome-c-reductase and NAD.H2-diaphorase in the brain, myocardium and kidneys increases. Under histotoxic hypoxia the level of iron in the tissues increases by 52-93%, that of copper--by 28-36%, of zinc--by 21-74% and of cobalt by 28-40%. There existed a positive correlation between the content of iron and the activity of NAD-dependent enzymes. In nonlethal form of histotoxic hypoxia the content of nonhemin iron and the activity of NAD.H2-cytochrome-c-reductase in the mitochondria of the brain increases by 25% and 17%, respectively, and a direct correlation is revealed between them.
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PMID:[Iron, copper, zinc and cobalt content and activity of respiratory metalloenzymes in animal tissues under toxic hypoxia]. 68 69

A lauric acid monooxygenase which catalyzes the formation of hydroxylaurate from lauric acid has been characterized in ageing tissues of Jerusalem artichoke (Helianthus tuberosus L.) tuber. Three reaction products have been identified from the mass fragmentation pattern of their methyltrimethylsilyl derivatives: 10-hydroxylauric acid, 9-hydroxylauric acid and 8-hydroxylauric acid. Enzyme activity is located on the microsomal fraction which also carries cytochrome P-450 and NADPH cytochrome-c reductase. The apparent Km of the enzyme for lauric acid is 0.97 micronM. Laurate monooxygenation is dependent upon O2 and inhibited by CO. The latter effect is light reversible. NADPH is the preferred electron donor although appreciable NADH-sustained activity was observed. NADPH cytochrome c reductase is involved in electron transfer as evidenced by the inhibitory effects of NADP+ and oxidized cytochrome c on laurate monooxygenation. Thus, the enzyme catalyzing laurate oxidation in Jerusalem artichoke tuber tissues appears to be a typical (cytochrome P-450)-linked monooxygenase.
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PMID:A microsomal (cytochrome P-450)-linked lauric-acid-monooxygenase from aged Jerusalem-artichoke-tuber tissues. 71 Apr 15

In the presence of hepatic microsomes, styrene produced a type I difference spectrum, which demonstrates that styrene binds to the catalytic site of ferricytochrome P-450. A comparison of the binding parameters for the interaction of styrene with noninduced, phenobarbital-induced, and 3-methylcholanthrene-induced microsomes indicated that styrene is predominantly bound by cytochrome P-450 and not by cytochrome P-448. Inhalation exposure to a mixture of acetone (1,000 ppm, 6 h/d) and styrene (300 ppm, 6 h/d) for 5 d caused a distinct decrease in hepatic free nonprotein sulfhydryl groups. This decrease could be observed both with and without phenobarbital treatment. Acetone inhalation alone also enhanced ethoxycoumarin O-deethylase activity in rats without pretreatments. Acetone inhalation also increased the cytochrome P-450 content of liver microsomes, but it had no effect on NADPH cytochrome c reductase or epoxide hydratase activity. Combined exposure to styrene and acetone enhanced NADPH cytochrome c reductase activity in nonphenobarbital-treated rats, but no effect was seen in the phenobarbital-treated animals. Phenobarbital treatment of animals can greatly modify the biotransformation and toxicity of styrene, phenobarbital inducible P-450 hemoprotein playing a predominant role in its metabolism. Simultaneous inhalation exposure to acetone also interacts with the metabolism of styrene.
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PMID:Interaction of styrene and acetone with drug biotransformation enzymes in rat liver. 73 16

Effect of Di(2-ethylhexyl) phthalate (DEHP), was investigated on chemical constituents and activity of certain enzymes of rat liver. A significant increase in liver weight; total and relative to body weight; decrease in total, free and esterified cholesterol; and no change in dry weight, moisture; RNA, DNA, total lipids, phospholipids, pyruvic acid and lactic acid contents was observed in liver of DEHP-treated rats as compared to controls. Activity of 3 mitochondrial enzymes, malic dehydrogenase, cytochrome-c-oxidase and diaphorase were significantly decreased while that of NADH-cytochrome c reductase, RNAase and DNAase remained unaltered upon treatment. The results suggest that DEHP exerts its hepatotoxic effects by interfering with bioenergetics of the cell.
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PMID:Effect of Di-(2-ethylhexyl) phthalate (DEHP) on chemical constituents and enzymatic activity of rat liver. 73 83

The interaction between amphetamine and synthetic oral contraceptive steroids have been studied in the female rat. A progestational agent, quingestanol acetate, and a standard combination contraceptive (quingestanol acetate/ethynyl estradiol) were given with and without the concurrent administration of amphetamine. Steroid treatments increased the activity of some drug-metabolizing enzymes (aminopyrine N-demethylase, coumarin 3- hydroxylase, hexobarbital oxidase). Other parameters measured remained unaltered (glucose-6-phosphatase, aniline hydroxylase, cytochrome c reductase, cytochrome P 450, microsomal protein and phospholipid contents). Amphetamine treatment alone raised some drug-metabolizing enzymes (coumarin 3-hydroxylase, hexobarbital oxidase), increased microsomal phospholipid content and de novo synthesis, but elicited no effect on other enzymes measured. Amphetamine and quingestanol acetate given together significantly increased some drug metabolizing enzymes while the simultaneous treatment with combined steroids and amphetamine showed the most pronounced action. These experiments thus revealed that at least in the liver of the female rat, amphetamine elicited no overt hepatotoxicity, rather, brought about a weak inductive action of drug metabolizing enzymes. The application of steroid hormones also raised drug metabolism and the interaction between amphetamine and contraceptive steroids showed additive effects.
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PMID:Influence of oral contraceptives on the acute effect of amphetamine on the hepatic endoplasmic reticulum of the rat. 84 78

The effect of ethinyl estradiol, a steroid commonly used in birth control pills and possibly associated with impaired drug metabolism in humans, on the activity of and turnover of components of the hepatic microsomal mixed-function oxidase system was studied in male rats. After 5 days of ethinyl estradiol, 5 mg/kg/day, there was a significant decrease in the activity of ethylmorphine-N-demethylase and in cytochrome P-450, cytochrome b2, and NADPH cytochrome c reductase. Cytochrome P-450 apoproteins were identified within an SDS-polyacrylamide gel system, and the rate of turnover of cytochrome P-450 apoproteins was studied by double-isotope labeling techniques. After 5 days of ethinyl estradiol administration, the rate of degradation of cytochrome P-450 apoprotein was reduced (half-life of 50 hr compared to 24 hr in control), and their relative rate of synthesis was likewise reduced, indicating that a new steady state of protein turnover associated with reduced synthesis rate had been reached. This was confirmed by studies of the effect of ethinyl estradiol on the level of microsomal cytochrome P-450 over a 10-day period.
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PMID:Effects of ethinyl estradiol on hepatic microsomal proteins and the turnover of cytochrome P-450. 92 82

Intact but fragile mitochondria were isolated from unsporulated oocysts of Eimeria tenella. The mitochondria respired in response to succinate, malate plus pyruvate, and L-ascorbate at rates of 1.00, 0.40, and 0.25 mu1 O2/min/mg protein, respectively. Spectrophotometric analyses of the cytochromes in mitochondria and whole oocysts revealed b-type and o-type cytochromes, at roughly similar levels, but no cytochrome c could be detected. The mitochondrial respiration was inhibited by cyanide, azide, carbon monoxide, antimycin A, and 2-heptyl-4-hydroxyquinoline-N-oxide, but was relatively resistant to rotenone and amytal. The quinolone coccidiostats buquinolate, amquinate, methyl benzoquate, and decoquinate were identified as very powerful inhibitiors of succinate and malate plus pyruvate supported respiration in E. tenella mitochondria. None of these four drugs exhibited any inhibitory effect on chicken liver mitochondria. Only 3 pmol of the quinolones per mg mitochondrial protein was needed to achieve 50% inhibition. The inhibition could not be reversed by coenzymes Q6 or Q10. Since the quinolones did not affect L-ascorbate-supported respiration or the activities of submitochondrial succinate dehydrogenase and NADH dehydrogenase, the site of action of the quinolone coccidiostats was tentatively identified as probably near cytochrome b in E. tenella mitochondria. Mitochondria isolated from an E. tenella amquinate-resistant mutant were much less susceptible to quinolone coccidiostats; 50% inhibition was attained by 300 pmol of the drugs/mg mitochondrial protein. The results suggest that the mechanisms of action of quinolone coccidiostats is by inhibiting the cytochrome-mediated electron transport in the mitochondria of coccidia. 2-Hydroxynaphthoquinone coccidiostats were identified as inhibitors of mitochondrial respiration of both E. tenella and chicken liver. They inhibited submitochondrial succinate dehydrogenase and NADH dehydrogenase of E. tenella, and remained equally active against the mitochondrial function of E. tenella amquinolate-resistant mutant.
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PMID:Studies of the mitochondria from Eimeria tenella and inhibition of the electron transport by quinolone coccidiostats. 117 97

Incubation of rat homogeneous detergent-solubilized cytochrome b5 with rat liver microsomes resulted in specific binding of the hemoprotein which was rapidly reduced by NADH. The NADH cytochrome c reductase activity in these preparations increased in proportion to the amount of cytochrome bound. However, the extra-bound detergent-solubilized cytochrome b5 did inhibit NADPH-dependent N-demethylations, the NADH synergism and NADPH cytochrome P-450 reductase activity. Manganese protoporphyrin-apocytochrome complex when bound to microsomes in amounts equivalent to detergent-solubilised cytochrome b5 showed no effect on N-demethylation activity. Furthermore, the binding of cytochrome b5 preparations reconstituted from heme and apocytochrome b5 had no effect on either the NADPH-dependent N-demethylation of aminopyrene or ethylmorphine or the NADH synergism observed with rat liver microsomes. In addition, homogeneous cytochrome b5 eluted from three additional Sephadex G-100 columns showed no inhibitory effects when bound to liver microsomes. Spectral analyses of the acid-acetone extract of the hemoprotein showed an absorption peak at 278 nm suggesting that the homogeneous b5 contains contaminating amounts of tightly bound detergent which is responsible for the observed inhibition of mixed function oxidase activity and which is removed during extraction of the heme from the apocytochrome and during further gel filtration applications.
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PMID:Binding of homogeneous cytochrome b5 to rat liver microsomes. Effect on N-demethylation reactions. 119 70

Mitochondria used in the present study were isolated from skeletal muscle of normal and thyroidectomized rats. The preparations were controlled by electron microscopy. It was not possible to find any morphological change induced by thyroidectomy, nevertheless, some difference appeared in the cytochrome contents which were slightly decreased. Oxygen consumption rates of thyroidectomized rat mitochondria were decreased when the particles were maintained in states 3 and 4 in the presence of various substrates, but the P/O ratios were not modified. The activities of mitochondrial enzymes were in general slightly affected by thyroidectomy except for glycerol-1-phosphate cytochrome c reductase and NADH rotenone sensitive cytochrome c reductase which were decreased and for glutamate dehydrogenase activity which was increased. The tRNA nucleotidyltransferase activity found in the mitochondrial matrix was not influenced by the absence of thyroid secretion. Normal rat muscle mitochondria incorporate 14C-leucine with an artificial ATP-generating system or with a respiratory substrate. The amino acid incorporation was decreased by thyroidectomy. Muscle mitochondria analyzed by polyacrylamide gel electrophoresis contained more than 30 protein components with MW ranging from 10.000 to 135.000. Thyroidectomy lowered the amount of a fraction of about 54.000 MW. It is not impossible that all the data observed in the absence of thyroid secretion are in relation with changes induced in the mitochondrial genome as previously shown in mitochondria isolated from liver or thyroidectomized rats.
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PMID:[Effects of thyroidectomy of the rat on the structure and functions of skeletal muscle mitochondria]. 120 23

Preparations with a selectively decreased (by 85-90%) content of NADH dehydrogenase were isolated by means of heating treatment of M. lysodeikticus isolated membranes. The degree of the reduction of the NADH dehydrogenase nearest neighbour in the respiration chain of cytochrome b556 in heated membranes is similar to that in intact membranes. It is concluded that cytochrome b556 and (or) NADH dehydrogenase are capable to lateral migration in the membrane of M. lysodeikticus, resulting in the inter-chain electrone transport. A coefficient of their lateral diffusion is calculated (D equals 8-10(-10)-2-10(-9) CM2SEC-1 At 30 degrees C) on the basis of kinetics of cytochrome reduction by NADH dehydrogenase. The electron transport, due to a diffusion of respiration carriers from one assambly to another, proceeds 100 times as slow as the electrone transport in the respiratory chain. The data obtained allow to consider the aggregation of respiration enzymes as a dynamic formation.
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PMID:[Lateral diffusion of the protein components of the respiratory assembly of Microsoccus lysodeikticus]. 121 62


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