Enzymatic Regulation of the Metabolism of Phosphoenolpyruvate in Tetrahymena pyriformis

The enzymes of phosphoenolpyruvate metabolism, i.e. P-enolpyruvate carboxykinase, P-enolpyruvate carboxylase, and pyruvate kinase, have been compared in Tetrahymena pyriformis under growth conditions which favor either gluconeogenesis or glycolysis. The activity of the cytosol P-enolpyruvate carboxy...

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Bibliographic Details
Published in:The Journal of biological chemistry 1972-05, Vol.247 (9), p.2755-2762
Main Authors: Diesterhaft, Martin D., Hsieh, Hsiang-Chuan, Elson, Charles, Sallach, H. James, Shrago, Earl
Format: Article
Language:English
Subjects:
Aerobiosis
Alcohol Oxidoreductases - metabolism
Animals
Carboxy-Lyases - isolation & purification
Carboxy-Lyases - metabolism
Chromatography, Gel
Chromatography, Ion Exchange
Cytoplasm - enzymology
Electrophoresis
Gluconeogenesis
Glucose - pharmacology
Glycolysis
Isocitrates
Isoenzymes
Lactates
Lyases - metabolism
Mitochondria - enzymology
Oxaloacetates
Phosphoenolpyruvate - metabolism
Pyruvate Kinase - isolation & purification
Tetrahymena pyriformis - cytology
Tetrahymena pyriformis - drug effects
Tetrahymena pyriformis - enzymology
Tetrahymena pyriformis - growth & development
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Summary:The enzymes of phosphoenolpyruvate metabolism, i.e. P-enolpyruvate carboxykinase, P-enolpyruvate carboxylase, and pyruvate kinase, have been compared in Tetrahymena pyriformis under growth conditions which favor either gluconeogenesis or glycolysis. The activity of the cytosol P-enolpyruvate carboxykinase is high in glucose-free and low in glucose-supplemented medium, while there is no change in activity of the mitochondrial enzyme. The chromatographic separation of the cytosol and mitochondrial enzymes on DEAE-Sephadex and Sephadex G-200 indicate that they are isozymes with distinct molecular properties. Both P-enolpyruvate carboxylase and pyruvate kinase activities are higher in glucose-supplemented medium. Distribution studies indicate an exclusive mitochondrial location for P-enolpyruvate carboxylase and cytosol location for pyruvate kinase. The peroxisomal enzymes, isocitrate lyase, malate synthetase, and lactic acid oxidase, as well as the cytosol P-enolpyruvate carboxykinase, adapt to changes in aeration as well as to glucose supplementation of the culture. Certain important enzymatic similarities as well as differences were observed between Tetrahymena and other organisms, including mammals.
ISSN:0021-9258
1083-351X
DOI:10.1016/S0021-9258(19)45276-9