Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aromatic-amino-acid-glyoxylate aminotransferase was highly purified from the mitochondrial fraction of livers from monkey and glucagon-injected rats. The two enzyme preparations showed physical and enzymic properties different from a kynurenine aminotransferase previously described. The two enzymes had nearly identical molecular weights (approximate 80 000), isoelectric points (pH 8.0) and pH optima (pH 8.0 - 8.5). However, a difference in substrate specificity was observed between the two enzymes. Both enzymes utilized glyoxylate, pyruvate, hydroxypyruvate and 2-oxo-4-methyl-thiobutyrate as effective amino acceptors. 2-Oxoglutarate was active for rat enzyme but not for monkey enzyme. With glyoxylate, amino donors were effective in the following order of activity; phenylalanine greater than histidine greater than tyrosine greater than tryptophan greater than 5-hydroxytrypotphan greater than kynurenine for the rat enzyme, and phenylalanine greater than kynurenine greater than histidine greater than tryptophan greater than 5-hydroxy-tryptophan for the monkey enzyme.
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PMID:Purification and characterization of aromatic-amino-acid-glyoxylate aminotransferase from monkey and rat liver. 2 37

2-Oxoglutarate was found to inhibit purified rat liver phosphoenolpyruvate carboxykinase when the assay was performed in the direction of either phosphoenolpyruvate or oxaloacetate synthesis. The inhibition was competitive with respect to oxaloacetate or phosphoenolpyruvate, the Ki values being 0.32 +/- 0.04 mM 0.63 +/- 0.19 mM respectively. 2-Oxoglutarate inhibited non-competitively when tested against GTP or Mn2+. The reported cytosolic concentrations of 2-oxoglutarate in rat hepatocytes are such that the enzyme is likely to be significantly inhibited under basal conditions. The cytosolic concentration of 2-oxoglutarate is known to fall precipitously under the influence of glucagon and other hormones that stimulate gluconeogenesis, and it is suggested that the hormone-induced decrease in 2-oxoglutarate content would alleviate the inhibition of phosphoenolpyruvate carboxykinase and stimulate flux from oxaloacetate to phosphoenolpyruvate. The implications of this finding to the rationalization of the role of pyruvate kinase in the stimulation of gluconeogenesis in the fasted state are discussed.
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PMID:Physiological concentrations of 2-oxoglutarate regulate the activity of phosphoenolpyruvate carboxykinase in liver. 149 14

Hepatocytes isolated from livers of rats with various models of acute uremia (binephrectomy, ureter ligation, uranyl nitrate-induced, or ischemic ARF) were incubated with glucagon, adrenalin, or cyclic AMP using serine as a substrate. A marked increase in glucose production was observed in the hepatocytes of uranyl nitrate-treated, binephrectomized, and ureter-ligated rats compared to starved controls or sham-operated animals. This effect was strengthened in the presence of glucagon, adrenaline, or cyclic AMP. In liver cells of binephrectomized and ureter-ligated animals, the production of acetoacetate and beta-hydroxybutyrate was significantly higher than in controls and sham-operated rats. Oxoglutarate and ATP production was only enhanced after ureter ligation. The correlation between glucose concentration and the cytosolic redox state was different in control and sham-operated rats than in either uremic group. This study confirms earlier investigations of a key role of serine in carbohydrate metabolism in acutely uremic rats.
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PMID:Effect of serine on gluconeogenic ability of hepatocytes in acute uremia. 633 Apr 26