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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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Book ChapterDOI
01 Jan 1974
TL;DR: The measurements of neutral fat by the determination of glycerol by chemical or fluorimetric methods require extraction and careful isolation of triglycerides followed by hydrolysis, but the isolation or purification of the triglycerides or the extraction of fat can be omitted.
Abstract: Publisher Summary Triglycerides with the phosphatides, and the free and esterified cholesterol, make up the quantitatively most important lipid fractions of blood. Adipose tissue has the highest triglyceride content, between 60 and 85 %. The measurements of neutral fat by the determination of glycerol by chemical or fluorimetric methods require extraction and careful isolation of triglycerides followed by hydrolysis. In the enzymatic determination of triglycerides in blood serum or plasma, the isolation or purification of the triglycerides or the extraction of fat can be omitted. The glycerol present in serum, plasma, or Folch extracts of tissues before and after ethanolic-alkaline hydrolysis is converted to glycerophosphate and adenosine diphosphate (ADP) with ATPand glycerokinase. The ADP reacts with pyruvate kinase and added phosphoenolpyruvate to give that is reduced to lactate with NADH and lactate dehydrogenase.

197 citations

Journal ArticleDOI
TL;DR: It is discovered that central metabolism is self-adapting to synchronize redox metabolism when respiration is activated, and this autonomous reconfiguration of central carbon metabolism prevents oxidative stress upon shifts between fermentation and respiration.

195 citations

Journal ArticleDOI
TL;DR: The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, Hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokin enzyme and phosphofructkinase could play an important role in the regulation of glycolytic flux in these cells.
Abstract: 1. Maximal activities of some key enzymes of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle and glutaminolysis were measured in homogenates from a variety of normal, neoplastic and suppressed cells. 2. The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokinase and phosphofructokinase could play an important role in the regulation of glycolytic flux in these cells. 3. The activity of pyruvate kinase is considerably higher in tumorigenic cells than in non-tumorigenic cells and higher in metastatic cells than in tumorigenic cells: for non-tumorigenic cells the activities range from 28.4 to 574, for tumorigenic cells from 899 to 1280, and for metastatic cells from 1590 to 1627 nmol/min per mg of protein. 4. The ratio of pyruvate kinase activity to 2 x phosphofructokinase activity is very high in neoplastic cells. The mean is 22.4 for neoplastic cells, whereas for muscle from 60 different animals it is only 3.8. 5. Both citrate synthase and isocitrate dehydrogenase activities are present in non-neoplastic and neoplastic cells, suggesting that the full complement of tricarboxylic-acid-cycle enzymes are present in these latter cells. 6. In neoplastic cells, the activity of glutaminase is similar to or greater than that of hexokinase, which suggests that glutamine may be as important as glucose for energy generation in these cells.

193 citations

Journal ArticleDOI
TL;DR: The identified pyruvate kinase catalyzes a crucial step in the conversion of photosynthate into oil, suggesting a preferred plastid route from its substrate phosphoenolpyruvates to fatty acids.
Abstract: Glycolysis is a ubiquitous pathway thought to be essential for the production of oil in developing seeds of Arabidopsis thaliana and oil crops. Compartmentation of primary metabolism in developing embryos poses a significant challenge for testing this hypothesis and for the engineering of seed biomass production. It also raises the question whether there is a preferred route of carbon from imported photosynthate to seed oil in the embryo. Plastidic pyruvate kinase catalyzes a highly regulated, ATP-producing reaction of glycolysis. The Arabidopsis genome encodes 14 putative isoforms of pyruvate kinases. Three genes encode subunits α, β1, and β2 of plastidic pyruvate kinase. The plastid enzyme prevalent in developing seeds likely has a subunit composition of 4α4β1, is most active at pH 8.0, and is inhibited by Glu. Disruption of the gene encoding the β1 subunit causes a reduction in plastidic pyruvate kinase activity and 60% reduction in seed oil content. The seed oil phenotype is fully restored by expression of the β1 subunit–encoding cDNA and partially by the β2 subunit–encoding cDNA. Therefore, the identified pyruvate kinase catalyzes a crucial step in the conversion of photosynthate into oil, suggesting a preferred plastid route from its substrate phosphoenolpyruvate to fatty acids.

193 citations

Journal ArticleDOI
TL;DR: The results are in good agreement with current ideas on the mechanism of aerobic glucose fermentation by trypanosomatids, and suggest that, under the experimental conditions used, both T. cruzi and C. fasciculata used glucose perferentially over amino acids for growth.

193 citations


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