Search results for "Pyruvate"

Neuron-specific enolase--a serum marker for malignant melanoma.

1989

AKT-independent signaling downstream of oncogenic PIK3CA mutations in human cancer.

2009

SummaryDysregulation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway occurs frequently in human cancer. PTEN tumor suppressor or PIK3CA oncogene mutations both direct PI3K-dependent tumorigenesis largely through activation of the AKT/PKB kinase. However, here we show through phosphoprotein profiling and functional genomic studies that many PIK3CA mutant cancer cell lines and human breast tumors exhibit only minimal AKT activation and a diminished reliance on AKT for anchorage-independent growth. Instead, these cells retain robust PDK1 activation and membrane localization and exhibit dependency on the PDK1 substrate SGK3. SGK3 undergoes PI3K- and PDK1-dependent activation in PI…

2012

Abstract. Global change forces ecosystems to adapt to elevated atmospheric concentrations of carbon dioxide (CO2). We understand that carbonyl sulfide (COS), a trace gas which is involved in building up the stratospheric sulfate aerosol layer, is taken up by vegetation with the same triad of the enzymes which are metabolizing CO2, i.e. ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), phosphoenolpyruvate carboxylase (PEP-Co) and carbonic anhydrase (CA). Therefore, we discuss a physiological/biochemical acclimation of these enzymes affecting the sink strength of vegetation for COS. We investigated the acclimation of two European tree species, Fagus sylvatica and Quercus ilex, grown …

Effect of changes in the cellular energy state on glucose transport activity in Brevibacterium flavum

2000

Abstract The effect of changes in cellular energy state on 6[14C]glucose uptake and activity of the phosphoenolpyruvate:glucose phosphotransferase system (PTS) in Brevibacterium flavum RC 115 cells was investigated. Energy generation in cells was varied by adding an inhibitor of cellular respiration (potassium cyanide) and an uncoupler of oxidative phosphorylation (pentachlorophenol) to the cell culture as well as by changing thiamine concentration in the bacterial growth medium. The results showed that glucose uptake in ‘respiring’ cells was inversely correlated with bacterial respiration activity: uptake declined with excess ATP generation and increased with lower ATP synthesis caused by …

Myc Promoter-Binding Protein-1 (MBP-1) Is a Novel Potential Prognostic Marker in Invasive Ductal Breast Carcinoma

2010

BackgroundAlpha-enolase is a glycolytic enzyme that catalyses the formation of phosphoenolpyruvate in the cell cytoplasm. α-Enolase and the predominantly nuclear Myc promoter-binding protein-1 (MBP-1) originate from a single gene through the alternative use of translational starting sites. MBP-1 binds to the P2 c-myc promoter and competes with TATA-box binding protein (TBP) to suppress gene transcription. Although several studies have shown an antiproliferative effect of MBP-1 overexpression on several human cancer cells, to date detailed observations of α-enolase and MBP-1 relative expression in primary tumors versus normal tissues and their correlation with clinicopathological features ha…

ENO1 gene product binds to the c-myc promoter and acts as a transcriptional repressor: relationship with Myc promoter-binding protein 1 (MBP-1).

2000

The Myc promoter-binding protein-1 (MBP-1) is a 37-38 kDa protein that binds to the c-myc P2 promoter and negatively regulates transcription of the protooncogene. MBP-1 cDNA shares 97% similarity with the cDNA encoding the glycolytic enzyme alpha-enolase and both genes have been mapped to the same region of human chromosome 1, suggesting the hypothesis that the two proteins might be encoded by the same gene. We show here data indicating that a 37 kDa protein is alternatively translated from the full-length alpha-enolase mRNA. This shorter form of alpha-enolase is able to bind the MBP-1 consensus sequence and to downregulate expression of a luciferase reporter gene under the control of the c…

Molecular characterization of a phosphoenolpyruvate carboxylase in the gymnosperm Picea abies (Norway spruce)

1996

Phosphoenolpyruvate carboxylase (PEPC) genes and cDNA sequences have so far been isolated from a broad range of angiosperm but not from gymnosperm species. We constructed a cDNA library from seedlings of Norway spruce (Picea abies) and identified cDNAs coding for PEPC. A full-length PEPC cDNA was sequenced. It consists of 3522 nucleotides and has an open reading frame (ORF) that encodes a polypeptide (963 amino acids) with a molecular mass of 109551. The deduced amino acid sequence revealed a higher similarity to the C3-form PEPC of angiosperm species (86-88%) than to the CAM and C4 forms (76-84%). The putative motif (Lys/Arg-X-X-Ser) for serine kinase, which is conserved in all angiosperm …

Manipulating mtDNA in vivo reprograms metabolism via novel response mechanisms.

2019

Mitochondria have been increasingly recognized as a central regulatory nexus for multiple metabolic pathways, in addition to ATP production via oxidative phosphorylation (OXPHOS). Here we show that inducing mitochondrial DNA (mtDNA) stress in Drosophila using a mitochondrially-targeted Type I restriction endonuclease (mtEcoBI) results in unexpected metabolic reprogramming in adult flies, distinct from effects on OXPHOS. Carbohydrate utilization was repressed, with catabolism shifted towards lipid oxidation, accompanied by elevated serine synthesis. Cleavage and translocation, the two modes of mtEcoBI action, repressed carbohydrate rmetabolism via two different mechanisms. DNA cleavage activ…

The Dissociation Constant of Pyruvic Acid: Determination by Spectrophotometric Measurements

1991

Aqueous solutions of sodium pyruvate/hydrochloric acid mixtures were studied with regard to changes in the intensity of optical absorption at 317 nm wavelength, caused by varying pH and temperature. The data were evaluated to determine the pyruvic acid apparent dissociation constant at infinite dilution. Its temperature dependence followed the relation ln Kod = −(0.55 ± 0.47) − (1538 ± 135)/T or, if previous results of Pedersen at two temperatures are included, In Kod = −(0.97 ± 0.35) − (1418 ± 102)T. The effective absorption coefficient for pyruvic acid and its anion differ because the former species is largely hydrated, whereas the latter is not. The known hydration constant and its tempe…

Phosphoenolpyruvate Carboxylase Activity and Malate Content of Spruce Needles of Healthy and Damaged Trees at Three Mountain Sites

1991

Summary Investigations were carried out on the phosphoenolpyruvate carboxylase (PEPC) activity and the malate content in spruce trees [Picea abies (L.) Karst] at three natural sites. In needles of damaged spruce the PEPC activity is significantly higher than in needles of undamaged spruce. Therefore, the PEPC activity seems to be a biochemical damage indicator in spruce needles. The increase in PEPC activity in damaged trees is discussed as a repair mechanism to compensate the increased need of carbon skeletons by providing oxaloacetate. The malate content is enhanced in needles of severely damaged trees. An increase in malate seems to indicate senescence reactions and may be related to the…