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Pyruvate kinase

About: Pyruvate kinase is a research topic. Over the lifetime, 5683 publications have been published within this topic receiving 180020 citations. The topic is also known as: ATP:pyruvate 2-O-phosphotransferase & phosphoenolpyruvate kinase.


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Journal ArticleDOI
TL;DR: It is demonstrated that aspirin causes the acetylation of multiple proteins whose molecular weight ranged from 20 to 200 kDa, and selective inhibition of glucose-6-phosphate dehydrogenase may represent an important mechanism by which aspirin may exert its anti-cancer effects through inhibition of ribonucleotide synthesis.
Abstract: Epidemiological and clinical observations provide consistent evidence that regular intake of aspirin may effectively inhibit the occurrence of epithelial tumors; however, the molec- ular mechanisms are not completely understood. In the present study, we determined the ability of aspirin to acetylate and post- translationally modify cellular proteins in HCT-116 human colon cancer cells to understand the potential mechanisms by which it may exerts anti-cancer effects. Using anti-acetyl lysine anti- bodies, here we demonstrate that aspirin causes the acetylation of multiple proteins whose molecular weight ranged from 20 to 200 kDa. The identity of these proteins was determined, using immuno-affinity purification, mass spectrometry and immuno- blotting. A total of 33 cellular proteins were potential targets of aspirin-mediated acetylation, while 16 were identified as common to both the control and aspirin-treated samples. These include enzymes of glycolytic pathway, cytoskeleton proteins, histones, ribosomal and mitochondrial proteins. The glycolytic enzymes which were identified include aldolase, glyceraldehyde-3-phos - phate dehydrogenase, enolase, pyruvate kinase M2, and lactate dehydrogenase A and B chains. Immunoblotting experiment showed that aspirin also acetylated glucose-6-phosphate dehy- drogenase and transketolase, both enzymes of pentose phosphate pathway involved in ribonucleotide biosynthesis. In vitro assays of these enzymes revealed that aspirin did not affect pyruvate kinase and lactate dehydrogenase activity; however, it decreased glucose 6 phosphate dehydrogenase activity. Similar results were also observed in HT-29 human colon cancer cells. Selective inhi- bition of glucose-6-phosphate dehydrogenase may represent an important mechanism by which aspirin may exert its anti-cancer effects through inhibition of ribonucleotide synthesis.

54 citations

Journal ArticleDOI
TL;DR: Carbohydrate metabolism during the development of fruits of the tomato cultivar Micro-Tom was studied and the metabolism of the pericarp and placental tissues was found to be different.
Abstract: Carbohydrate metabolism during the development of fruits of the tomato cultivar Micro-Tom was studied. The metabolism of the pericarp and placental tissues was found to be different. Starch was degraded more slowly in the placenta in comparison with the pericarp, whereas soluble sugars accumulated to a greater extent in the pericarp. The activities of glycolytic enzymes tended to peak at 40 days after flowering. Two of these, phosphoenolpyruvate phosphatase and pyruvate kinase, showed a dramatic increase in activity just before this peak, possibly indicating a role in up-regulating glycolysis to generate increased ATP that would be used during climacteric respiration. The expression of plastidial transporters was studied. Both the TPT and Glu6P transporter were expressed greatest in green fruits, before declining. The expression of the triose-phosphate transporter was greater than that of the glucose 6-phosphate transporter. The ATP/ADP transporter was expressed to a low level throughout fruit development.

54 citations

Journal ArticleDOI
TL;DR: It is argued that plant cells respond to phosphate deprivation by reconfiguring the flux distribution through the pathways of carbohydrate oxidation to take advantage of better phosphate homeostasis in the plastid.
Abstract: Understanding the mechanisms that allow plants to respond to variable and reduced availability of inorganic phosphate is of increasing agricultural importance because of the continuing depletion of the rock phosphate reserves that are used to combat inadequate phosphate levels in the soil. Changes in gene expression, protein levels, enzyme activities and metabolite levels all point to a reconfiguration of the central metabolic network in response to reduced availability of inorganic phosphate, but the metabolic significance of these changes can only be assessed in terms of the fluxes supported by the network. Steady-state metabolic flux analysis was used to define the metabolic phenotype of a heterotrophic Arabidopsis thaliana cell culture grown on a Murashige and Skoog medium containing 0, 1.25 or 5 mm inorganic phosphate. Fluxes through the central metabolic network were deduced from the redistribution of (13) C into metabolic intermediates and end products when cells were labelled with [1-(13) C], [2-(13) C], or [(13) C6 ]glucose, in combination with (14) C measurements of the rates of biomass accumulation. Analysis of the flux maps showed that reduced levels of phosphate in the growth medium stimulated flux through phosphoenolpyruvate carboxylase and malic enzyme, altered the balance between cytosolic and plastidic carbohydrate oxidation in favour of the plastid, and increased cell maintenance costs. We argue that plant cells respond to phosphate deprivation by reconfiguring the flux distribution through the pathways of carbohydrate oxidation to take advantage of better phosphate homeostasis in the plastid.

54 citations

Journal ArticleDOI
TL;DR: With increasing population doubling in vitro, human diploid fibroblasts exhibited a highly significant increase in glucose uptake from the growth medium and a corresponding increase in lactate production.
Abstract: With increasing population doubling in vitro, human diploid fibroblasts exhibited a highly significant increase in glucose uptake from the growth medium and a corresponding increase in lactate production. The switch to glycolysis occurred prior to the onset of changes in intracellular glucose and lactate concentrations or in the specific activity of the glycolytic regulatory enzyme, pyruvate kinase. It also preceded the morphological alterations held to be characteristic of cellular senescence.

54 citations

Journal ArticleDOI
15 Feb 2003-Blood
TL;DR: The molecular basis for pyruvate kinase (PK) deficiency in a white male patient with severe nonspherocytic hemolytic anemia is established and site-directed mutagenesis of the promoter region revealed the presence of a putative regulatory element (PKR-RE1) whose core binding motif, CTCTG, is located between nt -87 and nt-83.

54 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023215
2022201
2021147
2020166
2019150
2018138