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Pyruvate dehydrogenase kinase

About: Pyruvate dehydrogenase kinase is a research topic. Over the lifetime, 4224 publications have been published within this topic receiving 161052 citations. The topic is also known as: [pyruvate dehydrogenase (lipoamide)] kinase & pyruvate dehydrogenase (lipoamide) kinase.


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Journal ArticleDOI
TL;DR: Clinical findings are presented for 30 patients with lactic acidemia in whom activity of the pyruvate dehydrogenase complex in fibroblasts was significantly (P = less than 0.01) below that of control cell lines.

168 citations

Journal ArticleDOI
TL;DR: Deletion of PDC5 did not cause any decrease in the specific pyruvate decarboxylase activity while pdc1 deletion mutants had 80% of the wild-type activity, which indicates that PDC1 and P DC5 are the only structural genes for pyruVateDecarboxyase in yeast.
Abstract: Recently we deleted the pyruvate decarboxylase structural gene PDC1 from the genome of the yeast Saccharomyces cerevisiae. The pdc1 deletion mutants had pyruvate decarboxylase activity due to the presence of a second structural gene [Schaaff, I., Green, J. B. A., Gozalbo, D. & Hohmann, S. (1989) Curr. Genet. 15, 75-81]. We cloned and sequenced this gene which we call PDC5. The predicted amino acid sequences of PDC1 and PDC5 are 88% identical. Deletion of PDC5 did not cause any decrease in the specific pyruvate decarboxylase activity while pdc1 deletion mutants had 80% of the wild-type activity. Deletion mutants lacking both PDC1 and PDC5 did not show any detectable pyruvate decarboxylase activity in vitro and were unable to ferment glucose. This indicates that PDC1 and PDC5 are the only structural genes for pyruvate decarboxylase in yeast. The PDC5 isoenzyme showed a slightly higher Km value for its substrate pyruvate than the PDC1 product (PDC5: Km = 8 mM; PDC1: Km = 5 mM), as measured in crude extract of pdc1 and pdc5 deletion mutants, respectively. PDC5 is only expressed in pdc1 deletion mutants. No mRNA transcribed from PDC5 could be detected in wild-type cells. Thus, in addition to the control by glucose induction, pyruvate decarboxylase activity seems to be subject to autoregulation. Similar phenomena have been described previously for tubulin, histones and a ribosomal protein but not for metabolic enzymes.

167 citations

Journal ArticleDOI
01 May 2000-Diabetes
TL;DR: High-fat feeding leads to selective upregulation of PDK4 expression in slow-twitch muscle in response to high-Fat feeding in vivo, which is associated with a pronounced loss of sensitivity ofPDK activity to acute inhibition by pyruvate.
Abstract: In using Western blot analysis with antibodies raised against recombinant pyruvate dehydrogenase kinase (PDK) isoforms PDK2 and PDK4, this study demonstrates selective PDK isoform switching in specific skeletal muscle types in response to high-fat feeding that is associated with altered regulation of PDK activity by pyruvate. The administration of a diet high in saturated fats led to stable (approximately 2-fold) increases in PDK activities in both a typical slow-twitch (soleus [SOL]) muscle and a typical fast-twitch (anterior tibialis [AT]) muscle. Western blot analysis revealed that high-fat feeding significantly increased (approximately 2-fold; P < 0.001) PDK4 protein expression in SOL, with a modest (1.3-fold) increase in PDK2 protein expression. The relative increase in PDK4 protein expression in SOL was associated with a 7.6-fold increase in the pyruvate concentration that was required to elicit a 50% active pyruvate dehydrogenase complex, which indicates a marked decrease in the sensitivity of PDK to inhibition by pyruvate. In AT muscle, high-fat feeding elicited comparable (1.5- to 1.7-fold) increases (P < 0.05) in PDK4 and PDK2 protein expression. Loss of sensitivity of PDK to inhibition by pyruvate was less marked. The data suggest that a positive correlation exists between increases in PDK4 expression and the propensity with which muscles use lipid-derived fuels as respiratory substrates rather than with the degree of insulin resistance induced in skeletal muscles by high-fat feeding. In conclusion, high-fat feeding leads to selective upregulation of PDK4 expression in slow-twitch muscle in response to high-fat feeding in vivo, which is associated with a pronounced loss of sensitivity of PDK activity to acute inhibition by pyruvate. Thus, increased PDK4 expression may underlie the stable modification of the regulatory characteristics of PDK observed in slow-twitch muscle in response to high-fat feeding.

166 citations

Journal ArticleDOI
09 Dec 1966-Science
TL;DR: The biological significance of the inhibition of the key glycolytic enzymes is interpreted as a feedback inhibitory mechanism in regulation of fatty acid biosynthesis and may function for rapid adaptation by which the organism can use the fatty acid level as a metabolic directional switch in decreasing glyCOlysis and turning on gluconeogenesis.
Abstract: Increasing concentrations of sodium octanoate were progressively inhibitory to the activities of glucokinase, hexokinase, phosphofructokinase, and pyruvate kinase. Glucose-6-phosphate and 6-phosphogluconate dehydrogenases were also markedly inhibited. Other enzymes of carbohydrate metabolism such as lactate dehydrogenase, phosphohexose isomerase, and fructose-1,6-diphosphatase were not decreased. Among the key glycolytic enzymes, the inhibition of pyruvate kinase by the fatty acid was most marked. The biological significance of the inhibition of the key glycolytic enzymes is interpreted as a feedback inhibitory mechanism in regulation of fatty acid biosynthesis. The mechanism may function for rapid adaptation by which the organism can use the fatty acid level as a metabolic directional switch in decreasing glycolysis and turning on gluconeogenesis.

166 citations

Journal ArticleDOI
TL;DR: The results suggest that a mechanism common to all three agents is responsible for transmitting the stimulation from the plasma membrane to the mitochondrial components of the mixture, which required plasma membranes and could not be produced by treatment of mitochondria alone.
Abstract: The addition of insulin to a mixture of plasma membrane and mitochondrial fractions from rat adipocytes results in a decrease in the phosphorylation of a mitochondrial protein identified as the α subunit of pyruvate dehydrogenase [pyruvate:lipoamide oxidoreductase (decarboxylating and acceptor-acetylating), EC 1.2.4.1] (Seals, J. R., McDonald, J. M. & Jarett, L. (1979) J. Biol. Chem. 254, 6991-6996). This study confirms the prediction that a corresponding increase in pyruvate dehydrogenase activity can be effected by insulin treatment of this preparation. Incubation of the plasma membrane/mitochondria mixture with ATP inhibited pyruvate dehydrogenase activity as measured in a subsequent enzyme assay. The presence of insulin during this incubation with ATP resulted in a 24.5% stimulation of enzyme activity compared to incubation without insulin (n = 9, P < 0.001). The effect was specific for biologically active insulin and was insulin dose-dependent in the physiological range of insulin. Supermaximal doses of insulin produced reduced effects. An insulin effect of similar magnitude could also be observed when the plasma membrane/mitochondria mixture was incubated without ATP. Two insulin mimickers, concanavalin A and antibody to insulin receptor, stimulated pyruvate dehydrogenase by 30.4% (n = 6, P <0.001) and 28.1% (n = 8, P<0.001), respectively. Both of these agents also produced reduced effects at supermaximal concentrations. The effects of all three agents required plasma membranes and could not be produced by treatment of mitochondria alone. The results suggest that a mechanism common to all three agents is responsible for transmitting the stimulation from the plasma membrane to the mitochondrial components of the mixture.

165 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202329
202234
202161
202063
201959
201851