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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)

We propose the following scheme for cerebral uptake and overall metabolism of glucose in vivo: that brain selects from two pools of glucose anomers in arterial blood, that it takes up excess glucose, that glucose enters the brain tissue as glucose-6-phosphate through the actions of mutarotase and hexokinase, that some glucose-6-phosphate becomes metabolized to CO2 and some becomes incorporated into brain carbon pools, and that excess glucose-6-phosphate leaves brain through glucose-6-phosphatase and mutarotase activities. This results from our observations in arterio-venous studies for the determination of cerebral metabolism in humans in vivo that the cerebral uptake of [14C]glucose often appeared to differ from that of unlabeled glucose. With rapidly falling arterial radioactivity, unlabeled glucose uptake was more than [14C]glucose. With rising arterial radioactivity, [14C]glucose extraction exceeded unlabeled glucose. Studies with [14C]glucose-6-phosphate suggested that glucose-6-phosphatase in brain removes excess substrate by dephosphorylation. However, when arterial [14C]glucose increased slowly, [14C]glucose uptake varied considerably and the data resembled human cerebral metabolism of glucose anomers. An experiment employing [13C]glucose and NMR provided further support for our proposed scheme.
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PMID:Evidence for the cerebral uptake in vivo from two pools of glucose and the role of glucose-6-phosphatase in removing excess substrate from brain. 298 20

The anomeric form of glucose produced by glucose-6-phosphatase was studied using an apparatus that specifically measures beta-D-glucose. The time course of beta-D-glucose formation from glucose-6-P by glucose-6-phosphatase is essentially linear. In the presence of mutarotase, this rate is reduced to 70% of that obtained in the absence of mutarotase. When detergent treated microsomes were used, the rate of beta-D-glucose formation is unaffected by mutarotase. These results suggest that only beta-anomer of glucose is produced by microsomal glucose-6-phosphatase and this specificity is determined by translocase for glucose-6-P or glucose. It was also demonstrated that alpha-D-glucose is the substrate for glucokinase.
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PMID:Anomer specificity of glucose-6-phosphatase and glucokinase. 302 93