Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.9 (glucose-6-phosphatase)
 3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unlike halogenated benzenes, trichlorophenols did not induce xenobiotic metabolism in the rat. 2,3,5-, 2,3,6-, 2,4,5-, and 2,4,6-Trichlorophenol at doses as high as 400 mg/kg p.o. daily for 14 days did not alter EPN detoxification. Only 2,4,5-trichlorophenol at the highest dose decreased microsomal NADPH-cytochrome c reductase activity and cytochrome P-450 content. In vitro, all 4 isomers inhibited EPN detoxification and the demethylation of p-nitroanisole. UDP-glucuronyltransferase was not altered in vivo and was only slightly inhibited in vitro by 2,3,5- and 2,4,5-trichlorophenol. The compounds were not hepatotoxic as assessed by measurement of hepatic glucose-6-phosphatase and serum sorbitol dehydrogenase.
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PMID:Effect of trichlorophenols on xenobiotic metabolism in the rat. 10 51

The transverse distribution of enzyme proteins and phospholipids within microsomal membranes was studied by analyzing membrane composition after treatment with proteases and phospholipases. Upon trypsin treatment of closed microsomal vesicles, NADH- and NADPH-cytochrome c reductases as well as cytochrome b5 were solubilized or inactivated, while cytochrome P-450 was partially inactivated. When microsomes were exposed to a concentration of deoxycholate which makes them permeable to macromolecules but does not disrupt the membrane, the detergent alone was sufficient to release four enzymes: nucleoside diphosphatase, esterase, beta-glucuronidase, and a portion of the DT-diaphorase. Introduction of trypsin into the vesicle lumen inactivated glucose-6-phosphatase completely and cytochrome P-450 partially. The rest of this cytochrome, ATPase, AMPase, UDP-glucuronyltransferase, and the remaining 50% of DT-diaphorase activity were not affected by proteolysis from either side of the membrane. Phospholipase A treatment of intact microsomes in the presence of albumin hydrolyzed all of the phosphatidylethanolamine, phosphatidylserine, and 55% of the phosphatidylcholine. From this observation, it was concluded that these lipids are localized in the outer half of the bilayer of the microsomal membrane; Phosphatidylinositol, 45% of the phosphatidylcholine, and sphingomyelin are tentatively assigned to the inner half of this bilayer. It appears that the various enzyme proteins and phospholipids of the microsomal membrane display an asymmetric distribution in the transverse plane.
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PMID:Enzyme and phospholipid asymmetry in liver microsomal membranes. 19 Feb 41

Levels of cytochrome P-450 and the activities of amino-pyrinedemethylase and p-nitrophenol-UDP-glucuronyltransferase were measured in homogenates and microsomes of 16 to 19 day old chicken embryos exposed in ovo to phenobarbital. The activities of glucose-6-phosphatase were measured on the 19th day of incubation. After the highest dose of 3 X 8 mg phenobarbital, cytochrome P-450 increased 3-6fold, aminopyrinedemethylase activity 7fold and the activity of p-nitrophenol-UDP-glucuronyltransferase 3fold. Glucose-6-phosphatase activity was not increased but decreased. Corresponding to the given dose of phenobarbital (3X3, 3X4, 3X6, 3X8 mg) into the yolk sac an increase in enzyme activity levels mentioned above could as a rule be demonstrated at the level of p less than 0.0025. Calculated microsomal protein amounted to 43.0+/-6.5 mg/g liver.
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PMID:[Dose-dependent effects on phenobarbital on microsomal liver enzymes of chicken embryos (author's transl)]. 19 20

The results of a comparative biochemical and electron-microscopic study of membrane-injuring effect of N-nitrosodimethylamine--a chemical carcinogen widespread in the environment are reviewed. It has been established that in vivo and in vitro membrane-injuring effect of nitrosodimethylamine is characterized by reduced activity of membrane-bound enzymes of endoplasmic reticulum (UDP-glucuronyltransferase and glucose-6-phosphatase) accompanied by alterations in functional morphology of cells and intracellular structure.
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PMID:[Comparative biochemical and electron microscopic research on the membrane-damaging action of a chemical carcinogen on the endoplasmic reticulum in vivo and in vitro]. 310 62

We have examined the interactions of the histidine-specific reagent diethyl pyrocarbonate (DEPC) with the components of the rat hepatic glucose-6-phosphatase system (EC 3.1.3.9). DEPC is the first known reagent that satisfies the criteria of an active-site-specific label for the phosphohydrolase component. (a) It inactivates through formation of a stable covalent bond. (b) It is effective at reasonably low concentrations (2-4 mM) under relatively mild conditions (e.g. 30 degrees C at neutral pH). (c) Inactivation is substantially blocked by glucose 6-phosphate, Pi and NaF, compounds which are known to interact quite specifically with the phosphohydrolase. (d) Under conditions where glucose 6-phosphate and NaF protect the enzyme, no protection is provided against DEPC-mediated inactivation of two other functional components of the membrane, the glucose 6-phosphate translocase and UDP-glucuronyltransferase. DEPC also shows potential for use at 0 degree C as a label for UDP-glucuronyltransferase.
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PMID:Specific inactivation of the phosphohydrolase component of the hepatic microsomal glucose-6-phosphatase system by diethyl pyrocarbonate. 608 98

Haptoglobin, albumin, glucose-6-phosphatase, p-nitrophenol uridine diphosphate (UDP)-glucuronosyltransferase and cytochrome P-450 were measured in liver microsomes from normal rats and from rats undergoing an acute inflammatory reaction (AIR) induced either by subcutaneous administration of turpentine or by intrapleural injection of calcium pyrophosphate. 24 h after the beginning of the AIR induced by subcutaneous administration of turpentine, haptoglobin and albumin, two exported proteins, had risen to a peak (+313%), and dropped considerably (-52%) whereas nonexported protein levels did not change except for cytochrome P-450, which diminished (-38%). In the same way, intrapleural injection of calcium pyrophosphate was followed after 24 h by significant but smaller variations in haptoglobin (+60%) and cytochrome P-450 (-20%) concentrations. Albumin levels, glucose-6-phosphatase and p-nitrophenol UDP-glucuronosyltransferase activities were unchanged in this experimental model. The drop in cytochrome P-450 under all these conditions and also the diminution of albumin in the first model suggest that all the proteins produced by liver cells might not be synthesized in equal amounts. The decrease in cytochrome P-450 could interfere in hepatic drug metabolism during an AIR.
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PMID:Study of biochemical behavior of some exported and nonexported hepatic proteins during an acute inflammatory reaction in the rat. 608 20

To gain insight into the cause of the latency of microsomal hexose-6-phosphate dehydrogenase activity, changes in the activity and latency of hexose-6-phosphate dehydrogenase were examined to determine whether they were parallel to those of other microsomal enzymes (UDP glucuronyltransferase, nucleoside diphosphatase and glucose-6-phosphatase) during development and after treatments of rats with phenobarbital and a high carbohydrate diet. We also examined whether the latency of hexose-6-phosphate dehydrogenase could be ascribed to changes in the cholesterol content and phospholipid composition of microsomes under various conditions. The results show that the activities and latencies of the four microsomal enzymes change independently during development and after various treatments, and that the phospholipid composition of microsomes does not have any direct effect on the latency of hexose-6-phosphate dehydrogenase.
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PMID:Alterations in the latency of hepatic microsomal hexose-6-phosphate dehydrogenase under various in vivo and in vitro conditions. 626 29

The chemoprotection extended by eugenol against carbon tetrachloride (CCl4) intoxication was established by studies on drug-metabolizing phase I and phase II enzymes. An overall decrease in drug-metabolizing enzymes, namely NADPH-cytochrome c reductase, NADH-cytochrome reductase, coumarin hydroxylase, 7-ethoxy coumarin-O-deethylase, UDP-glucuronyltransferase and glutathione-S-transferase, was observed with CCl4 intoxication, with a subsequent decrease in cytochrome P450 and cytochrome b5 content. CCl4 caused a significant decrease in microsomal phospholipids and the marker enzymes glucose-6-phosphatase and 5'-nucleotidase, and an increase in thiobarbituric acid reactive substances (TBARS). Simultaneous administration of eugenol with CCl4 inhibited the accumulation of TBARS and the decrease in the microsomal phospholipids and marker enzymes. Further, the chemical onslaught imposed by CCl4 on the drug-metabolizing system was removed successfully by eugenol. Eugenol appears to act as an in vivo antioxidant and as a better inducer of phase II enzymes than phase I enzymes. It is therefore suggested that eugenol could be an interesting basic structure for drug design.
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PMID:Effect of eugenol on drug-metabolizing enzymes of carbon tetrachloride-intoxicated rat liver. 778 11