Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.1.32 (phosphoenolpyruvate carboxykinase)
 4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of depletion of tricarboxylic acid cycle intermediates by isolated rat heart mitochondria was studied using hydroxymalonate (an inhibitor of malic enzymes) and mercaptopicolinate (an inhibitor of phosphoenolpyruvate carboxykinase) as tools. Hydroxymalonate inhibited the respiration rate of isolated mitochondria in state 3 by 40% when 2 mM malate was the only external substrate, but no inhibition was found with 2 mM malate plus 0.5 mM pyruvate as substrates. In the presence of bicarbonate, arsenite and ATP propionate was converted to pyruvate and malate at the rates of 14.0 +/- 2.9 and 2.8 +/- 1.8 nmol/mg protein in 5 min, respectively. Under these conditions, 0.1 mM mercaptopicolinate did not affect this conversion, but 2 mM hydroxymalonate inhibited pyruvate formation completely and resulted in an accumulation of malate up to 13.2 +/- 2.9 nmol/mg protein. No accumulation of phosphenolpyruvate was found under any condition tested. It is concluded that malic enzymes but not phosphoenolpyruvate carboxykinase, are involved in conversion of propionate to pyruvate in isolated rat heart mitochondria.
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PMID:The disposition of citric acid cycle intermediates by isolated rat heart mitochondria. 730 75

Metabolism of [U-13C]aspartate in cultured astrocytes and the effects of inhibitors of malic enzyme and phosphoenolpyruvate carboxykinase (hydroxymalonate and 3-mercaptopicolinic acid, respectively) were studied using 13C nuclear magnetic resonance (NMR) spectroscopy. The labelling of glutamate and glutamine showed entry of aspartate into the tricarboxylic acid (TCA) cycle after conversion to oxaloacetate. Production of [U-13C]pyruvate from [U-13C]aspartate was revealed by the presence of [U-13C]lactate in incubation media. Furthermore, labelling patterns in C-2 and C-3 in intracellular aspartate showed entry of [1,2-13C]acetyl-CoA into the TCA cycle; evidence for pyruvate-recycling. No reduction in [U-13C]lactate was observed in the presence of either enzyme inhibitor. However, 3-mercaptopicolinic acid reduced incorporation of labelled acetyl-CoA into TCA cycle intermediates, indicating compartmentation of pyruvate production in astrocytes.
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PMID:Lactate formation from [U-13C]aspartate in cultured astrocytes: compartmentation of pyruvate metabolism. 945 29