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)

Tissues from the cerebral cortex, liver and myocardium of a patient with Lafora disease were obtained at autopsy and were studied biochemically. 1. Glucose content in the myocardium and liver was almost nil while that in the controls was 0.66 mg/g wet weight in the former and 8.80 mg/g wet weight in the latter. Glycogen content in the cerebral cortex and myocardium was about 10 and 3 times more than in controls. 2. Polyglucosan extracted from the cerebral cortex, liver and myocardium had a longer exterior glucose chain than that in the liver of the control but a normal, alpha or beta 1,4-glucosidic linkage was observed. 3. The activities of glucose-6-phosphatase and amylo-1,6-glucosidase in the cerebral cortex, liver and myocardium were well preserved. The activities of acid maltase in the three organs mentioned above and of neutral maltase in the myocardium were elevated twice and one and half times more than the control. Phosphorylase levels in the myocardium were extremely small, while in the cerebral cortex and liver normal activities were observed. In light of these findings, glycogen metabolism in Lafora disease is discussed.
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PMID:Biochemical studies on tissues from a patient with Lafora disease. 17 19

A human hepatocyte line (HHY41) was established from normal human liver tissue. This cell line was derived from a primary culture of human hepatocytes maintained between two layers of collagen gel for 4 weeks. It differs from other human hepatocyte lines in that transfection with the simian virus 40 gene was not used for cellular transformation and nonhepatocellular coculture cells were not present. HHY41 cells have proliferated freely in serum and hormone-supplemented medium after more than 1 year in continuous culture, exhibiting typical morphological characteristics of hepatocytes. HHY41 cells retain glucose-6-phosphatase activity. They also retain the ability to secrete liver-specific proteins such as albumin, transferrin, and alpha-fetoprotein. Northern blot analysis confirmed the presence of albumin mRNA. Cytochromes P450 induced by polycyclic aromatic hydrocarbons are maintained in these cells. Detection of cell surface antigens revealed that HHY41 cells express alpha 1 beta 1-integrin, which is expressed by normal hepatocytes and not by bile duct epithelial cells. High-molecular-weight cytokeratin, a marker for bile duct cells, is also absent in HHY41. Cytogenetic analysis showed hyperdiploid karyotype with a consistent deletion in the short arm of chromosome 1. HHY41 can be considered a new human hepatocyte line which retains liver-specific functions of differentiated hepatocytes. Derived from normal liver tissue, not a hepatocellular carcinoma, it provides a new model system for studying the regulation of cell growth and differentiated functions in human hepatocytes.
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PMID:Establishment of a human hepatocyte line derived from primary culture in a collagen gel sandwich culture system. 749 48

Glycoprotein processing in Dictyostelium discoideum is characterized by enzyme catalyzed steps not reported in other organisms. One of these is the formation of a beta 1 --> 4 linkage between GlcNAc and the mannose linked to the core mannose in the alpha 1 --> 6 position of N-glycosides. A simple and sensitive assay for this GlcNAc transferase activity, using a tri-mannose acceptor and a low concentration of UDP-GlcNAc, was developed. Homogenates of the organism were subjected to sub-cellular fractionation by centrifugation in discontinuous sucrose gradients. The specific activity was enriched 4-5-fold in a crude membrane fraction. The transferase was purified 10-12-fold in a membrane fraction that bands on top of 1.1 M sucrose. This fraction was also enriched in nucleotidyldiphosphatase. The enriched fraction was deficient in glucose-6-phosphatase, an endoplasmic reticulum marker. Approx. 80% of the transferase activity was latent, and unavailable to protease. Purified membranes were either subjected to phase separation in Triton X-114, or sodium carbonate extraction or sonication. In each case, the transferase behaved as an intrinsic membrane protein. Several secreted and lysosomal proteins are modified by the enzyme. These data support the idea that the GlcNAc transferase is present as an integral Golgi membrane protein and that at least the catalytic center of the transferase is on the lumenal side of the vesicles.
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PMID:Subcellular distribution of "intersecting' beta-N-acetylglucosaminyltransferase in Dictyostelium discoideum. A likely marker for the Golgi apparatus. 865 99