Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alloxan diabetes induced in white rats by intraperitoneal injection of alloxan-monohydrate (15 mg/100 g body weight) was used to study changes in the glycogen phosphorylase a and b, phosphoprotein phosphatases and hexokinase activities under insulin deficiency conditions. Among the enzymes studied, an increase in muscle phosphorylase a activity as well as the a/b ratio have been obtained. In diabetic muscle phosphoprotein phosphatases and hexokinase activities were diminished. AMP increased the liver glycogen phosphorylase activity twice in diabetic rats whereas in normal animals the enzyme was less sensitive to this effector. The changes in liver hexokinase activity at diabetes were not connected and correlated with the altered phosphorylase and protein phosphatase activities. The logical chain of probable molecular events taking place in muscle glycogen metabolism under the conditions of insulin deficiency is offered.
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PMID:Changes in the activity of enzymes, participating in glycogen metabolism of alloxan diabetic rats. 255 79

The effect of increased expression of glycogen phosphorylase on glucose metabolism in human muscle was examined in primary cultured fibers transduced with recombinant adenovirus AdCMV-MGP encoding muscle glycogen phosphorylase. Increments of 20-fold in total enzyme activity and of 14-fold of the active form of the enzyme were associated with a 30% reduction in basal glycogen levels. Total glycogen synthase activity was doubled in AdCMV-MGP-transduced cells even though the activity ratio was decreased. Incubation with forskolin, which inactivated glycogen synthase and activated glycogen phosphorylase, induced greater net glycogenolysis in engineered cells. In unstimulated fibers, lactate production was three times higher in AdCMV-MGP fibers as compared with controls, despite similar rates of glycogenolysis. In transduced fibers incubated with 2-deoxyglucose, the level of 2-deoxyglucose 6-phosphate was about 8-fold elevated over the control even though hexokinase activity was unmodified in AdCMV-MGP fibers. Overexpression of glycogen phosphorylase also led to enhancement of [U-14C]glucose incorporation into glycogen, lactate, and lipid. Accordingly, determination of lipid cell content revealed that engineered cells were accumulating lipids. Furthermore, 14CO2 formation from [U-14C]glucose was 1.6-fold higher, whereas 14CO2 formation from [6-14C]glucose was unmodified, in AdCMV-MGP fibers. Our data show that in human skeletal muscle cells in culture, the increase in glycogen phosphorylase activity is able to up-regulate glycogen synthase activity indicating the enhancement of glycogen turnover. We suggest that the increase in glycogen phosphorylase and, thereby, in glycogen metabolism, is sufficient to enhance glucose uptake in the muscle cell. Glucose taken up by engineered muscle cells is essentially disposed of through nonoxidative metabolism and converted into lactate and lipid.
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PMID:Overexpression of muscle glycogen phosphorylase in cultured human muscle fibers causes increased glucose consumption and nonoxidative disposal. 857 26