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:3.1.3.9 (glucose-6-phosphatase)
3,081 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure is described for the preparation of a membrane fraction enriched in basal-lateral plasma membranes from gastric mucosa. Gastric glands isolated from rabbit were employed as starting material, greatly reducing contamination from non-glandular cell types. The distribution of cellular components during the fractionation procedure was monitored with specific marker enzymes. (Na+ + K+)-ATPase, ouabain-sensitive K+-stimulated p-nitrophenyl-phosphatase and histamine-stimulated adenylate cyclase were used as markers for basal-lateral membranes. These three markers were similarly distributed during both differential and equilibrium density gradient centrifugation. The enriched membrane fraction contained more than 30% of the total initial activities of the three basal-lateral membrane markers which were purified better than 11-fold with respect to protein. (Na+ + K+)-ATPase activity was resolved from the activities of acid phosphatase, pepsin, Mg2+-ATPase, cytochrome c oxidase, NADPH-cytochrome c reductase, glucose-6-phosphatase, (K+ + H+)-ATPase, DNA and RNA.
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PMID:An enriched preparation of basal-lateral plasma membranes from gastric glandular cells. 626 84

A zymogen granule fraction has been isolated from rat pancreas, and its purity has been assessed by biochemical and morphological criteria. Specific activities of two marker enzymes, amylase and chymotrypsin, are increased by 4.6 and 5.4-fold, respectively, as compared to the homogenate. The purified fraction is devoid of detectable RNA, DNA and 5'-nucleotidase, glucose-6-phosphatase, and cytochrome c oxidase activities. Electron micrographs confirm the absence of mitochondria, lysosomes, and rough endoplasmic reticulum fragments. Zymogen granule membranes were isolated from this fraction on a sucrose gradient following lysis in alkaline buffer. Secretory contaminants were efficiently removed from the membranes as indicated by experiments in which labeled secretory proteins were added during the isolation procedure and secondly by measuring residual levels of amylase and chymotrypsin. Three enzyme activities were found in the membranes: thiamine pyrophosphatase, ATP-diphosphohydrolase, and low levels of acid phosphatase. Membrane proteins were solubilized by urea-Triton X-100 and separated in double-dimension (isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Isoelectric point and molecular weight of each protein band were determined.
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PMID:Isolation of zymogen granules from rat pancreas and characterization of their membrane proteins. 629 Feb 20

Glucagon receptor levels, glucagon-stimulated and other forms of adenylyl cyclase activity, and regulatory component activity of adenylyl cyclase were determined in hepatic plasma membranes of rats administered streptozotocin without and with insulin to produce varying degrees of hyperglycemia. Receptor levels were assayed by direct binding of the specific probe [125I-Tyr10]-iodoglucagon; regulatory component activity was assayed by the capacity to reconstitute stimulatory regulation in deficient membranes from cyc- S49 murine lymphoma cells. In rats given 150 mg streptozotocin, glucagon stimulation of adenylyl cyclase as well as basal, sodium fluoride, 5' guanylylimidodiphosphate [GMP-P(NH)P] and Mn-dependent activities were reduced 50%, glucagon receptor levels but not affinity were reduced 67%, and regulatory component activity was decreased 50%. In addition, alpha 1-adrenergic receptors and 5'-nucleotidase were similarly reduced in diabetes. However, specific ouabain-inhibitable Na+, K+, ATPase activity was not altered by streptozotocin treatment. The streptozotocin-induced changes were noted within 24 h and became maximal by 120 h after its administration. All of these decreases were partially reversed by in vivo insulin treatment. DNA, cytochrome c oxidase, glucose-6-phosphatase, and N-acetyl-beta-glucosaminidase content in hepatic plasma membrane preparations were not substantially different in diabetic as compared with control animals. The data demonstrate that glucagon-mediated regulation of cyclic AMP formation is deranged in insulin deficiency owing to a combined decrease in receptors, derangement of the coupling mechanism intervening between receptor and adenylyl cyclase, and possibly, an altered basal effector system. Some of these changes appear to reflect a "desensitization-like" phenomenon which may or may not be attributable to the hyperglucagonemia of diabetes mellitus. There also appears to be a concurrent generalized decrease in several but not all plasma membrane receptor and enzymatic proteins. This may be the result of a number of processes among which is the accelerated proteolysis of uncontrolled diabetes.
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PMID:Glucagon-stimulable adenylyl cyclase in rat liver. The impact of streptozotocin-induced diabetes mellitus. 632 32

Intramuscular injections of the title drug in a dose of 5 mg/kg (5% of the LD50) during 10 days produced in the liver and blood serum of white rats a decrease in the activity of glucokinase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glutathione reductase, ATPase and ceruloplasmin. The urea content in total phospholipids rose, whereas the content of triglycerides and hexosamine diminished. Ten and 20 days after the drug was discontinued the majority of these characteristics returned to normal. The activity of glucosophosphate isomerase, transketolase, glucose-6-phosphatase, fructose-1,6-diphosphatase and lactate dehydrogenase as well as the content of total cholesterol, free fatty acids, tyrosine, hydroxyproline, total protein, RNA and DNA remained unchanged.
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PMID:[Effect of decane-1,10-bis[acetoxy-(N, N)-dimethyl-(N)-(diphenylmethoxy-2-ethyl) ammonium] dichloride on metabolism in white rats]. 651 57

The metabolic enzymes alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2) and isocitrate dehydrogenase (EC 1.1.1.42) were measured in mucosal homogenates and these enzymes, together with glucose-6-phosphatase (EC 3.1.3.9), were measured in homogenates of isolated enterocytes from germ-free (GF) and conventional (CV) chicks which were either fed continuously until they were killed or were subjected to a 16 h fast before killing. The intestine of the GF chicks was generally lighter than that of the CV controls. The activity of alkaline phosphatase was greater in the mucosal homogenates of the CV chicks compared with the GF birds, but the concentrations of acid phosphatase and isocitric dehydrogenase were not different in the two groups. In the isolated enterocytes the concentration of all enzymes expressed per mg DNA, except alkaline phosphatase, was higher in the GF chicks. Expressed per mg protein there was no significant difference in enzyme activity in the two groups. Fasting caused a reduction in intestinal weight and total mucosal protein in both groups but the reduction was greater in the GF chicks compared with the CV controls. In the GF chicks, fasting caused a significant fall in acid phosphatase and isocitric dehydrogenase activities of the mucosal homogenate, whereas in the CV chicks only acid phosphatase fell to a significant extent. In the isolated enterocytes feeding caused a marked fall in protein per mg DNA in the CV chicks; fasting tended to reduce enzyme concentrations in the GF chicks but to have less effect in the CV group except for alkaline phosphatase where there was a marked rise in activity. It is suggested that the difference in enzyme activities in the mucosal homogenates and isolated enterocytes might resulted from (a) the presence of a much greater lamina propria in the CV compared with the GF chicks and (b) the greater mitotic activity in the fed CV chicks yielding a much larger number of smaller immature cells.
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PMID:The activities of some metabolic enzymes in the intestines of germ-free and conventional chicks. 663 33

The role of glucocorticosteroid and thyroid hormone and of glucagon and insulin in the pre- and postnatal developmental formation of carbamoyl-phosphate synthase, ornithine transcarbamoylase, arginase, glutamate dehydrogenase, tyrosine aminotransferase, glucose-6-phosphatase, hexokinase and glucokinase activities in rat liver was investigated. Glucocorticosteroids and a low insulin/glucagon ratio always stimulate formation of carbamoyl-phosphate synthase, ornithine transcarbamoylase, arginase, glutamate dehydrogenase, tyrosine aminotransferase and glucose-6-phosphatase, while glucocorticosteroids and a high insulin/glucagon ratio stimulate formation of glucokinase. Thyroid hormone stimulates the formation of carbamoyl-phosphate synthase, arginase and tyrosine aminotransferase only before birth, whereas it stimulates the formation of glutamate dehydrogenase and glucose-6-phosphatase both before and after birth. Ornithine transcarbamoylase activity is depressed after thyroid-hormone treatment before and after birth. DNA content is always decreased by glucocorticosteroids and increased by thyroid hormone. The effect of these hormones on hexokinase is complex, probably due to different responses of the constitutive isozymes. With the exception of the effects of thyroid hormone on carbamoyl-phosphate synthase, arginase and tyrosine aminotransferase before birth, which may be indirect, the responses of enzyme activities and DNA content to treatment with glucocorticosteroid hormones, glucagon, insulin and thyroid hormone are qualitatively the same in fetuses, neonates, sucklings, weanlings and adults. Thus, the developmental profiles of the enzyme clusters reflect the changing levels of the relevant hormones. The enzymes that are stimulated by glucocorticosteroids and the insulin/glucagon ratio show increases in enzyme activity perinatally and around weaning, and relatively low activities in between, while those enzymes that are additionally stimulated by thyroid hormone differ in exhibiting relatively high activities between birth and weaning.
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PMID:Multihormonal control of enzyme clusters in rat liver ontogenesis. II. Role of glucocorticosteroid and thyroid hormone and of glucagon and insulin. 702 60

Thirty-four independent nonviable c-locus mutations (types cal, albino lethal and cas, albino subvital), derived from radiation experiments, were tested for involvement of nearby markers tp, Mod-2, sh-1, and Hbb: 10, 22, and 2 involved, respectively, none of these markers, Mod-2 alone, and Mod-2 plus sh-1. When classified on this basis, as well as according to developmental stage at which homozygotes die, and by limited complementation results, the 34 independent mutations fell into 12 groups. From results of a full-scale complementation grid of all 435 possible crosses among 30 of the mutations, we were able to postulate an alignment of eight functional units by which the 12 groups fit a linear pattern. Abnormal phenotypes utilized in the complementation study were deaths at various stages of prenatal or postnatal development, body weight, and reduction or absence of various enzymes. Some of these phenotypes can be separated by complementation e.g., there is no evidence that mitochondrial malic enzyme influences survival at any age); others cannot thus be separated (e.g., glucose-6-phosphatase deficiency and neonatal death).--We conclude that all of the nonviable albino mutations are deficiencies overlapping at c, and ranging in size from less than 2cM to 6-11 cM. The characterization of this array of deficiencies should provide useful tools for gene-dosage studies, recombinant-DNA fine-structure analyses, etc. Since many of the combinations of lethals produce viable albino animals that resemble the standard c/c type, we conclude (a) that the c locus contains no sites essential for survival, and (b) that viable nonalbino c-locus mutations (cxv) are the result of mutations within the c cistron. Viable albinos (cav, the majority of radiation-induced c-locus mutations) may be intracistronic mutations or very small deficiencies.
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PMID:Analysis of the albino-locus region of the mouse: IV. Characterization of 34 deficiencies. 711 20

The livers of rats treated for 12 weeks with N-nitrosomorpholine (80 mg/1 drinking water) were investigated on the day of carcinogen withdrawal (12 + 0 weeks) and 8 weeks after cessation of treatment (12 + 8 weeks). The glycogen content in relation to the DNA and protein content of the liver and the activities of glycogen synthetase, glycogen phosphorylase, glucose-6-phosphatase, and glucose-6-phosphate dehydrogenase were determined in the liver homogenates. The glycogen content of the livers was slightly elevated at both times investigated. Phosphorylase and synthetase activities showed no clear alterations in livers of treated animals as compared with controls. Glucose-6-phosphatase activity was significantly reduced at 12 + 0 weeks and returned to normal values at 12 + 8 weeks. The activity of glucose-6-phosphate dehydrogenase was unchanged at 12 + 0 weeks, but exhibited a significant increase at 12 + 8 weeks. Polyacrylamide gel electrophoresis with staining of the gels by an assay specific for the glucose-6-phosphate-dehydrogenase-catalysed reaction revealed the same pattern of active bands in treated and untreated animals but with higher activities in two bands originating from extracts of nitrosomorpholine-treated livers.
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PMID:Biochemical correlation of glycogen content and activity of some enzymes of carbohydrate metabolism in rat liver during early stages of carcinogenesis. 713 Feb 54

Several recent studies suggest that jejunoileal bypass-induced liver disease results from malabsorption of essential nutrients. However, in experimental animals, resection of the defunctionalized bowel substantially reduces bypass-induced liver injury. Such models are often used to support the theory that bacteria in the defunctionalized bowel produce toxic substances which result in liver damage. We used a rat model to first explore the effects of intestinal bypass vs resection on various parameters of liver injury, and subsequently compared these findings to the effect of both bypass and resection on mucosal adaptation in the remaining intact bowel after each procedure. Bypassed animals had lower levels of hepatic cytochrome P-450, glucose-6-phosphatase, pentobarbital hydroxylase, and serum triglycerides than did animals undergoing resection of defunctionalized bowel. Concurrently, resected animals had much greater increases in mucosal weight, DNA content, and protein content in the intact bowel than did bypassed animals. We speculate that the beneficial effects of resection of bypassed bowel on liver function may be a result of increased mucosal hyperplasia in resected animals, rather than elimination of production of toxic substances in the defunctionalized bowel.
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PMID:Etiology of jejunoileal bypass-induced liver dysfunction in rats. 723 61

Imperatorin, oxypeucedanine and chalepin are furanocoumarins isolated from Clausena anisata a medicinal plant common in West Africa. Only chalepin is found to have anticoagulant activity when administered to rats at a single dose. Aniline hydroxylase activity was appreciably depressed by each of the substances. Ethylmorphine demethylase, hepatic DNA, reduced glutathione and glucose-6-phosphatase were unaffected by these compounds when administered at a dose of 50 mg/kg for 3 days prior to sacrifice. Under similar conditions only chalepin treatment resulted in alpha-1-globulin increase and a decrease in beta-globulin content of the serum. Intraperitoneal treatment with chalepin (100 mg/kg) for 2 days resulted in the death of 4 rats out of 10 within a 48 h of treatment. Livers of dead rats showed generalized necrosis of hepatocytes. No deaths were recorded for imperatorin and oxypeucedanine. Rats surviving after 8 weeks showed no changes in hepatic enzyme activity, reduced glutathione and DNA concentrations. However, chalepin and imperatorin induced alterations in the serum protein pattern within this period. Liver lesions were observed in chalepin treated animals and were characterized by very mild necrosis of hepatocytes. No lesions were observed in the livers of rats treated with imperatorin and oxypeucedanine.
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PMID:Structure-activity relationship in the toxicity of some naturally occurring coumarins-chalepin, imperatorin and oxypeucedanine. 726 93


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