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:1.6.99.3 (diaphorase)
5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of a single topical application of several nitroarenes (1-nitropyrene, nitropyrenes mixture, nitrobenzo(ghi)perylene mixture, 3-nitrofluoranthene, nitrofluoranthene mixture, and nitroperylene mixture) and their corresponding parent arenes to neonatal rats on hepatic and cutaneous drug and carcinogen metabolism was studied. Topical application of each nitroarene (10 mg/kg) resulted in significant induction of aryl hydrocarbon hydroxylase (AHH), 7-ethoxyresorufin O-deethylase (ERD), and 7-ethoxycoumarin O-deethylase (ECD) activities in both skin (1.5- to 14.6-fold) and liver (1.3- to 41.9-fold). The induction of these enzymes by each of the nitroarenes was significant when compared to control or to their corresponding parent arenes. Among the nitroarenes studied, 1-nitropyrene was the least effective in inducing enzyme activities. The inducibility in both skin and liver by different nitroarenes tested was in the following order: nitrofluoranthenes mixture greater than 3-nitrofluoranthene greater than nitroperylenes mixture greater than nitrobenzo(ghi)perylenes mixture greater than nitropyrenes mixture greater than 1-nitropyrene. The nitrofluoranthenes mixture and the nitroperylenes mixture were almost as effective as 3-methylcholanthrene (3-MC). Parent arenes were either ineffective or significantly less effective than nitrated arenes in inducing hepatic and/or cutaneous monooxygenase activities. Hepatic and/or cutaneous benzphetamine N-demethylase (BPD), NADPH cytochrome c reductase, NADH ferricyanide reductase activities, and the levels of cytochrome P-450 and cytochrome b5, remained unchanged following treatment with either topically applied nitroarenes or arenes. However, a shift of approximately 1 nm to the blue region in the absorption maximum of hepatic cytochrome P-450 was observed in animals treated with nitroarenes. This shift was not evident in the case of 1-nitropyrene. Analysis of benzo(a)pyrene metabolites by high-pressure liquid chromatography revealed a significant enhancement in the production of metabolites by nitroarene-treated rat skin and liver microsomes. Our studies suggest that nitroarenes are inducers of hepatic and cutaneous monooxygenases in neonatal rats after topical administration and that they resemble the 3-MC type of inducers in this regard.
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PMID:Comparative effects of topically applied nitrated arenes and their nonnitrated parent arenes on cutaneous and hepatic drug and carcinogen metabolism in neonatal rats. 349 18

Plasmodium yoelii nigeriensis infection in albino mice significantly altered the hepatic microsomal mixed function oxidase system. Cytochrome P-450 (the terminal monooxygenase) and other monooxygenases, viz. aniline hydroxylase, aminopyrine-N-demethylase and benzo(a)pyrene hydroxylase were significantly lowered while microsomal heme showed 4-fold increase at 80% parasitaemia. Noticeable impairment in the other components like NADH:cytochrome b5 reductase, NADPH:cytochrome c reductase, cytochrome b5 and glucose-6-phosphatase was also observed. Oral treatment of normal and P. y. nigeriensis infected mice with chloroquine (64 mg per kg body weight for 4 days) caused lowering of mixed function oxidase activities which however showed a recovering trend, a week after cessation of treatment.
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PMID:Effect of Plasmodium yoelii nigeriensis infection and chloroquine on the hepatic mixed function oxidase system of mice. 362 73

The cytochrome P-450 monooxygenase system of hamster liver microsomes and its response to prior treatment with ethanol and other xenobiotics have been examined. Male Syrian golden hamsters were administered ethanol (ETOH), phenobarbital (PB), 5,6-benzoflavone (BF) or isoniazid (INH). Each treatment resulted in a moderate increase (20-60%) in the specific content of liver microsomal cytochrome P-450 along with a unique hemeprotein ferrous carbonyl Soret maximum. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of liver microsomes revealed distinctive changes in protein banding patterns in the cytochrome P-450 (45-60 kDa) region with each treatment. NADPH: cytochrome c reductase activity was increased by both PB and INH, whereas cytochrome b5 content was increased by INH only. Microsomal oxidation of ETOH and aniline p-hydroxylation (expressed per nmol cytochrome P-450) were enhanced dramatically by ETOH and INH, whereas PB and BF had no effect on these enzymatic activities. Both ETOH and INH also increased zoxazolamine 6-hydroxylation but, in contrast to other rodent species, this drug-metabolizing activity was decreased in hamster liver microsomes after treatment with either PB or BF. Microsomal benzphetamine N-demethylation was decreased by ETOH, INH and BF administration and was only modestly enhanced after treatment with PB. ETOH and INH had no effect on the O-deethylation of 7-ethoxycoumarin, and enzymatic activity increased by BF but decreased by PB. These results demonstrate that the cytochrome P-450-dependent monooxygenase system of hamster liver microsomes responds to treatment with ETOH and other xenobiotics in a manner that is quantitatively and, in certain respects, qualitatively different from that reported for the rat, rabbit, and mouse.
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PMID:Characterization of the cytochrome P-450 monooxygenase system of hamster liver microsomes. Effects of prior treatment with ethanol and other xenobiotics. 367 19

Microsomes were prepared from bovine ciliary bodies. The contents of cytochrome P-450 and related components of the microsomal electron transport system were determined. The cytochrome P-450 content was 32 pmoles/mg protein, which was about 4% that in rat liver. The cytochrome b5 content was 59 pmoles/mg protein. The NADH-cytochrome c reductase and NADPH-cytochrome c reductase activities were 268 and 18 nmoles/min/mg protein, respectively. The ethoxyresorufin deethylase activity was 2.1 pmoles product formed/min/mg protein.
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PMID:Cytochrome P-450 and related components of the microsomal electron transport system in the bovine ciliary body. 374 14

The results of the present experiments have demonstrated that mitochondrial heme was transported to apocytochrome b5 incorporated into phospholipid vesicles in the presence of supernatant liver protein. The heme transfer depended on the concentration of supernatant protein, liposome-apocytochrome b5 and mitochondria, respectively. Omission of one of these components led to an almost complete loss of the transfer activity. The transport was a rapid reaction which showed an approximate linearity until 1.5 min at 37 degrees C after that became saturated. When the functional capacity was tested by the NADH-cytochrome c reductase system, the reconstituted cytochrome b5 expressed its complete original catalytic properties. The heme transfer activity was remarkably inhibited by KCN and NaN3, but was not affected by SH-reagent, such as N-ethylmaleimide and iodoacetate. ATP, EDTA and sodium fluoride had no effect. On the other hand, there was no evidence that supernatant protein participates in heme release from mitochondria or membrane fusion between mitochondria and phospholipid vesicles.
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PMID:[Heme transport from mitochondria to apocytochrome b5 incorporated into phospholipid vesicles by cytosolic liver protein]. 378 70

Effects of growth hormone on phospholipid composition and fatty acyl distribution were studied in liver mitochondria of hypophysectomized rats. After hypophysectomy, only cardiolipin showed a 25% decrease. Its fatty acyl distribution, which consisted mainly of linoleic acid (55-60%) and oleic acid (20%), was unchanged. In phosphatidylcholine and phosphatidylethanolamine fractions the contents of docosahexaenoic and arachidonic acids were decreased with a concomitant increase in linoleic acid content. These changes could be accounted for by small but significant decreases in the activities of delta 9-desaturase (sucrose-induced), delta 5-desaturase and mitochondrial elongation enzymes. The activities of delta 6-desaturase, NADH cytochrome b5 ferri-reductase, cytochrome b5, NADH cytochrome c reductase and microsomal elongation enzymes remained virtually unchanged. Injection of bovine growth hormone daily for seven days restored cardiolipin and fatty acyl distribution and the enzyme activities. From these and other results, we conclude that growth hormone-dependent increase of respiratory activity of liver mitochondria may be partly mediated by the hormonal effects on membrane lipid distribution.
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PMID:Growth hormone and liver mitochondria: effects on phospholipid composition and fatty acyl distribution. 379 32

The results of the present experiment are shown in terms of the transport of protoheme from mitochondria to apocytochrome b5 when fresh rat liver mitochondria, apocytochrome b5, and cytosol were incubated. The heme transfer protein was purified from rat liver cytosol up to approximately 133-140-fold with a 43% yield by the procedure discussed herein, including Sephadex G-75 and CM-cellulose column chromatography. The final preparation showed apparent homogeneity upon polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Its native form was found to be a dimeric protein with a Mr = 45,000 which consists of a subunit with a Mr = 23,000. In the transporting system, the heme transfer depended on the concentration of mitochondria (donor), apocytochrome b5 (acceptor), and purified transfer protein, respectively. Omission of one of these components led to an almost complete loss of the transfer activity. The transport of mitochondrial protoheme was a rapid reaction which showed approximate linearity until 1.5 min and after that it became saturated. When the functional capacity was tested by the NADH-cytochrome c reductase system, the reconstituted cytochrome b5 expressed its complete original catalytic properties, as well as its characteristic absorption spectra for the hemoprotein. Furthermore, the detailed physicochemical and immunological characterization of the transfer protein provided evidence that the protein is identical with soluble glutathione S-transferase, which conjugates glutathione with a variety of electrophilic compounds. At least one of the glutathione S-transferase isozymes observed was identified as GST-C2, which comprises the subunit of Yb'Yb' by the immunoprecipitation reaction using various anti-glutathione S-transferase isozyme antibodies.
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PMID:Purification and characterization of cytosolic liver protein facilitating heme transport into apocytochrome b5 from mitochondria. Evidence for identifying the heme transfer protein as belonging to a group of glutathione S-transferases. 392 64

Levels of cytochrome P-450 and cytochrome b5, and activities of NADPH cytochrome c reductase and 7-ethoxycoumarin O-deethylase, were found to be significantly decreased in hepatic microsomes prepared from mice killed 24 h after administration of a single intraperitoneal (i.p.) dose of adriamycin (ADR, 5 mg/kg). In contrast, both ascorbate-induced lipid peroxidation and conjugated dienes were increased in the same preparations. In vitro addition of ADR (5 micrograms/ml) to hepatic microsomal preparations (1 mg/ml protein) from the control mice also led to a substantial decrease in the mixed function oxidase (MFO) enzymes. A characteristic spectral change with an absorption peak at 408 nm and trough at 422 nm was associated with this in vitro interaction. It is suggested that the loss of cytochrome P-450 and related MFO enzymes due to ADR treatment is related to the generation of free radicals and subsequent lipid peroxidation in the liver.
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PMID:Depression of mouse liver microsomal mixed function oxidase enzymes by adriamycin. 393 35

A membrane-associated NADH dehydrogenase from beef neutrophils was purified to homogeneity, using detergent (cholate plus Triton X-100) extraction and chromatography on DEAE-Sepharose CL-6B, agarose-hexane-NAD, and hydroxylapatite. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed an apparent subunit molecular weight of 17,500, but the enzyme was highly aggregated (Mr greater than 450,000) in nondenaturing gels containing 0.1% Triton X-100. The protein band in nondenaturing gels was also stained for activity using NADH and nitro blue tetrazolium. The enzyme showed greatest electron acceptor activity with ferricyanide (100%), followed by cytochrome c (3.5%), dichloroindophenol (2.7%), and cytochrome b5 (0.34%). No activity was seen with oxygen. The Km values for NADH and ferricyanide were 18 and 9.5 microM, respectively, and NAD+ was a weak competitive inhibitor (Ki = 118 microM). No activity was seen with NADPH. No effects were seen with mitochondrial respiratory inhibitors such as azide, cyanide, or rotenone, but p-chloromercuribenzoate was strongly inhibitory and N-ethylmaleimide was weakly inhibitory. No free flavin was detectable in enzyme preparations. Based upon kinetic, physical, and inhibition properties, this NADH dehydrogenase differs from those previously described in microsomes and erythrocyte plasma membrane.
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PMID:NADH dehydrogenase from bovine neutrophil membranes. Purification and properties. 394 Oct 77

Cytochrome b5 has been purified from hamster liver microsomes. Both Ouchterlony double-diffusion and rocket immunoelectrophoresis experiments indicate that no immuno-cross-reactivity exists between guinea-pig anti-rabbit cytochrome b5 antibody and hamster cytochrome b5. However, anti-rabbit b5 IgG inhibited both hamster microsomal NADH-cytochrome c reductase and NADPH-dependent 7-ethoxycoumarin-O-deethylase activities. Hamster cytochrome b5 stimulated several reconstituted hamster cytochrome P-450-dependent monooxygenase activities and this stimulatory effect could be inhibited by antibody against rabbit cytochrome b5. Two-dimensional iodinated tryptic peptide mapping experiments provided evidence that the polypeptide fingerprint of hamster cytochrome b5 is substantially different from the fingerprints of cytochrome b5 isolated from rabbit, rat and bovine. We also studied the in vitro synthesis of hamster cytochrome b5 from liver mRNA using a wheat germ lysate system. A 16 kDa polypeptide, which is the same size as hamster cytochrome b5, was immunoprecipitated by antibody against rabbit b5. This experiment suggested that in vitro synthesized hamster cytochrome b5 is recognized by a heterologous antibody. Thus, hamster and rabbit cytochrome b5 do share some common immuno-determinants which may be located close to the heme-binding active site.
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PMID:Hamster hepatic cytochrome b5: purifications, immunochemical properties, and in vitro synthesis. 401 26


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