Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.4.1.1 (pyruvate carboxylase)
 1,516 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

New cytochemical method, based on biochemical experiments, was elaborated for the ultrastructural localization of phospho(enol)pyruvate carboxylase (EC 4.1.1.31). The procedure was used to study the saprophytic submerged mycelium of the ascomycetous fungus Claviceps purpurea Tul. producing clavine alkaloids. The pelleted mycelium was fixed in ice cold 3% glutaraldehyde in 50 mM cacodylate buffer pH 7.2 and washed repeatedly in the same cold buffer The reaction mixture contained 100 mM Tris-HCl buffer pH 9.0, 10 mM phospho(enol)pyruvate, 30 mM sodium potassium tartrate, 3 mM Pb(NO3)2, 60 mM MgCl2 and 30 mM NaHCO3. Enzyme activity was localized in vacuoles, particularly inside lipid globules (spherosomes) and less frequently in membranous vesicles. Acetyl-CoA activated PEP-carboxylase both in cell free extracts and in the cytochemical staining. Aspartate inhibited the enzyme in the biochemical assay with coupled malate dehydrogenase system; the cytochemical reaction was not influenced, probably due to the interference of asparagine synthase (EC 6.3.1.1).
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PMID:Electron-cytochemical localization of phospho(enol)pyruvate carboxylase (EC 4.1.1.31) in fungal cells. 739 80

The metabolism of [1,2-13C2]glucose and [U-13C4]3-hydroxybutyrate was studied in rat brain with in vivo and in vitro 13C NMR spectroscopy, taking advantage, in particular, of homonuclear 13C-13C spin coupling patterns. After infusion of [1,2-13C2]glucose or [U-13C4]3-hydroxybutyrate into rats, the uptake of the substrates in brain and their metabolism to [1-13C]bicarbonate could be detected with in vivo 13C NMR spectroscopy. At the end of the infusion experiment, methanol/HCl/HClO4 extracts of the brain tissue were further analysed by high resolution 13C NMR spectroscopy. The 13C spin coupling patterns revealed entirely different isotopomer distributions for the closely related cerebral metabolites glutamate, glutamine and 4-aminobutyric acid. A quantitative analysis of the 13C spectra demonstrated (i) the existence of two kinetically distinct pools of glutamate, (ii) a pronounced CO2 fixation via pyruvate carboxylase in the glial cells accounting for as much as 38% of the oxaloacetate synthesis in the glial tricarboxylic acid cycle, (iii) a cerebral pyruvate recycling system contributing maximally 17% of the pyruvate metabolism through the pyruvate dehydrogenase in neurons, and (iv) a predominant production of 4-aminobutyric acid from glutamate synthesized in the neurons. In addition, the labelling pattern of N-acetyl aspartate upon infusion of labelled glucose or 3-hydroxybutyrate provided insight into the synthesis of this compound in mammalian brain. While the acetyl moiety originates from the metabolic equivalent of the C-1-C-2 part of cerebral glutamate, the aspartyl moiety is not in direct contact with the intermediates of glycolysis or of the tricarboxylic acid cycles.
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PMID:Cerebral metabolism of [1,2-13C2]glucose and [U-13C4]3-hydroxybutyrate in rat brain as detected by 13C NMR spectroscopy. 810 58