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)

The correlation between the cytochemistry (glycoprotein, glycogen, glucose-6-phosphatase, catalase, alkaline phosphatase) and the growth rate of the fast-growing Morris hepatoma 3924A and the slow-growing Morris hepatoma 9618A was studied by utracytochemical techniques. By the chromic acid-phosphotungstic acid technique, acid glycoprotein is stained in glycocalyx, Golgi saccules and vesicles, and secretory granules of the tumor cells of both hepatomas. However, the hepatoma 3924A cells contain thicker glycocalyx and more numerous glycoprotein-rich granules than hepatoma 9618A cells. Abundant alpha and beta glycogen particles are found in hepatoma 3924A. Moderate glucose-6-phosphatase activity is observed in the cisternae of endoplasmic reticulum and nuclear envelope of hepatoma 9618A, but it is totally absent in hepatoma 3924A. High catalase activity is present in numerous peroxisomes of hepatoma 9618A. Hepatoma 3924A contains only a few catalase-positive microperoxisomes. Weak to moderate alkaline phosphatase is present in the plasma membrane and nuclear envelope of hepatoma 9618A cells, while hepatoma 3924A shows no activity of the enzyme. All the cytochemical parameters except glycoprotein show an inverse relationship with the growth rate of the hepatomas. The higher intracellular glycoprotein content of hepatoma 3924A may be related to differences in cell coat secretion (composition and activity) from the slower-growing hepatoma 9618A
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PMID:Correlation between growth rate and cytochemistry in Morris hepatomas. 627 86

Anterograde or retrograde perfusion of rat liver with digitonin selectively permeabilizes the periportal or the perivenous zone of the hepatic lobule. Digitonin perfusion is used to analyze the effluents released by permeabilized hepatocytes or, combined with collagenase perfusion, to obtain cell suspensions enriched in either periportal or perivenous hepatocytes. Despite the wide use of digitonin to study lobular heterogeneity, its affects on rat hepatocytes are not well documented. We therefore analyzed the effects of digitonin perfusion on the intracellular content of rat hepatocytes by combining electron microscopy, histoenzymology, immunohistochemistry, and in situ hybridization. At the concentration currently used for the study of lobular heterogeneity, digitonin perfusion induced a marked cytosolic clarification of permeabilized hepatocytes, while most organelles except mitochondria were well preserved. In the digitonin-altered zones, there was no histochemical detection of non-membrane-bound enzymes (lactate dehydrogenase, glutamate dehydrogenase), whereas membrane-bound enzymes (succinate dehydrogenase, beta-hydroxybutyrate dehydrogenase, NADPH dehydrogenase, glucose-6-phosphatase) were still detected. Immunohistochemistry and in situ hybridization revealed significant amounts of several plasma proteins (albumin, alpha 2-macroglobulin, alpha 1-inhibitor 3, alpha 1-acid glycoprotein) and their respective mRNAs in digitonin-permeabilized hepatocytes. The demonstration that digitonin-permeabilized hepatocytes retain many intracellular constituents shows that biochemical analysis of cellular effluents released from digitonin-permeabilized hepatocytes must be interpreted with caution and that the apparent characteristics of cell suspensions obtained by the digitonin-collagenase technique might be significantly altered by contamination with permeabilized hepatocytes from the opposite zone.
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PMID:Effects of digitonin on the intracellular content of rat hepatocytes: implications for its use in the study of intralobular heterogeneity. 815 38

Tachyzoites of Toxoplasma gondii multiplies within the parasitophorous vacuole (PV) of the host cell. Simultaneously with parasite division growth of the vacuole takes place. Using immunofluorescence microscopy and antibodies recognizing calreticulin, a nonmuscle functional analogue of calsequestrin, and a 76 kDa glycoprotein localized in the endoplasmic reticulum (ER), we showed the incorporation of ER elements of the host cell into parasitophorous vacuole containing-T. gondii. In addition enzyme cytochemistry showed that glucose-6-phosphatase, an enzyme marker of ER, is also localized within the PV. These observations suggest that growth of T. gondii -- containing PV is at least in part due to incorporation of elements of the host cell ER into the vacuole.
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PMID:Relationship between the host cell endoplasmic reticulum and the parasitophorous vacuole containing Toxoplasma gondii. 924 95

Glycogen storage disease type 1 (GSD-1), also known as von Gierke disease, is a group of autosomal recessive metabolic disorders caused by deficiencies in the activity of the glucose-6-phosphatase (G6Pase) system that consists of at least two membrane proteins, glucose-6-phosphate transporter (G6PT) and G6Pase. G6PT translocates glucose-6-phosphate (G6P) from cytoplasm to the lumen of the endoplasmic reticulum (ER) and G6Pase catalyzes the hydrolysis of G6P to produce glucose and phosphate. Therefore, G6PT and G6Pase work in concert to maintain glucose homeostasis. Deficiencies in G6Pase and G6PT cause GSD-1a and GSD-1b, respectively. Both manifest functional G6Pase deficiency characterized by growth retardation, hypoglycemia, hepatomegaly, kidney enlargement, hyperlipidemia, hyperuricemia, and lactic acidemia. GSD-1b patients also suffer from chronic neutropenia and functional deficiencies of neutrophils and monocytes, resulting in recurrent bacterial infections as well as ulceration of the oral and intestinal mucosa. The G6Pase gene maps to chromosome 17q21 and encodes a 36-kDa glycoprotein that is anchored to the ER by 9 transmembrane helices with its active site facing the lumen. Animal models of GSD-1a have been developed and are being exploited to delineate the disease more precisely and to develop new therapies. The G6PT gene maps to chromosome 11q23 and encodes a 37-kDa protein that is anchored to the ER by 10 transmembrane helices. A functional assay for the recombinant G6PT protein has been established, which showed that G6PT functions as a G6P transporter in the absence of G6Pase. However, microsomal G6P uptake activity was markedly enhanced in the simultaneous presence of G6PT and G6Pase. The cloning of the G6PT gene now permits animal models of GSD-1b to be generated. These recent developments are increasing our understanding of the GSD-l disorders and the G6Pase system, knowledge that will facilitate the development of novel therapeutic approaches for these disorders.
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PMID:The molecular basis of type 1 glycogen storage diseases. 1189 41

In the present study, the potential effects of 2-allyl amino 4-methyl sulfanyl butyric acid (AMSB) on the glucose metabolism and glycoprotein components in streptozotocin (STZ) induced experimental diabetic rats were determined. Further, molecular modeling was performed to investigate the modes of AMSB interaction with insulin receptor active sites. The blood glucose and plasma insulin levels were measured in the STZ induced diabetic rats, whereas the glucose metabolism and glycoprotein components were analyzed from the plasma and tissues. After oral treatment of AMSB there was a significant reduction in blood glucose, glucose-6-phosphatase, fructose-1,6-bisphosphatase and glycogen phosphorylase. On the other hand, the activity of the glycoprotein levels, such as hexose, hexosamine, fucose and sialic acid, were significantly reduced. In addition, a significant elevation in plasma insulin, hexokinase, glycogen and glycogen synthase were also observed in the AMSB treated rats. The molecular modeling study revealed that AMSB has a stable binding pattern to the active site of insulin, with a Gscore value of -7.34 Kcal mol-1. From this study we conclude that AMSB has a potent antidiabetic activity in addition to its protective effect on glycoprotein metabolism.
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PMID:Beneficial protective effects of 2-allyl amino 4-methyl sulfanyl butyric acid on glucose metabolism and glycoprotein components in streptozotocin induced diabetic rats with molecular modeling. 3009 Mar 55


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