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

A procedure is described for the purification of the enzyme indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (IAA-myo-inositol synthase). This enzyme catalyzes the transfer of indol-3-ylacetate from 1-0-indol-3-ylacetyl-beta-d-glucose to myo-inositol to form indol-3-ylacetyl-myo-inositol and glucose. A hexokinase or glucose oxidase based assay system is described. The enzyme has been purified approximately 16,000-fold, has an isoelectric point of pH 6.1 and yields three catalytically inactive bands upon acrylamide gel electrophoresis of the native protein. The enzyme shows maximum transferase activity with myo-inositol but shows some transferase activity with scyllo-inositol and myo-inosose-2. No transfer of IAA occurs with myo-inositol-d-galactopyranose, cyclohexanol, mannitol, or glycerol as acyl acceptor. The affinity of the enzyme for 1-0-indol-3-ylacetyl-beta-d-glucose is, Km = 30 micromolar, and for myo-inositol is, Km = 4 millimolar. The enzyme does not catalyze the exchange incorporation of glucose into IAA-glucose indicating the reaction mechanism involves binding of IAA glucose to the enzyme with subsequent hydrolytic cleavage of the acyl moiety by the hydroxyl of myo-inositol to form IAA myo-inositol ester.
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PMID:Partial purification and characterization of indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (indoleacetic acid-inositol synthase). 1153 69

Indole-3-acetic acid (IAA) is toxic for human tumor cells and in association with horseradish peroxidase (HRP) can be used as a new prodrug/enzyme combination for targeted cancer therapy. The toxic effect of IAA on neutrophils, macrophages and lymphocytes is associated with cell peroxidase activity, which is high in neutrophils and low in lymphocytes. The effect of IAA on glucose and glutamine metabolism in leukocytes presenting different peroxidase activities: neutrophils, thioglycollate-elicited macrophages and lymphocytes was investigated. A time-course effect (from 6 to 48 h in culture) of IAA on glucose and glutamine metabolism of neutrophils, thioglycollate-elicited macrophages, and lymphocytes was then carried out. Addition of IAA (0.25 mM) did not have a marked effect on glucose utilization and lactate formation by the three cell types but it raised glutamine consumption and glutamate production by neutrophils and macrophages. IAA had no effect on glutamine consumption and glutamate production by lymphocytes. A strong relationship was found between glutamine utilization (0.999) and glutamate production (0.999) and peroxidase activity. IAA did not change the activities of hexokinase, glucose-6-phosphate dehydrogenase, citrate synthase, lactate dehydrogenase, and phosphate-dependent glutaminase of 24 h cultured neutrophils and lymphocytes. The effect of IAA (1 mM) on glucose and glutamine metabolism was also investigated by 1 h incubated leukocytes in PBS. IAA did not affect glucose and glutamine metabolism of lymphocytes but enhanced glucose and glutamine metabolism by 1 h incubated neutrophils and thioglycollate-elicited macrophages. IAA caused a marked increase on oxygen consumption by neutrophils, which was more pronounced in the presence of the glutamine as compared to glucose. The stimulation of oxygen consumption leads to a reduction in NADH/NAD+ ratio that activates the flux of substrates through the Krebs cycle. Since glutamine is mainly metabolized through the left hand side of the Krebs cycle, a reduction in the redox state of the cells may accelerate the flux of substrates through glutaminolysis. The toxic results presented here show that the affect of IAA in association with peroxidase involves activation of glutamine metabolism.
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PMID:Indole-3-acetic acid increases glutamine utilization by high peroxidase activity-presenting leukocytes. 1526 71