Abstract
We have characterized the gene YOR347c of Saccharomyces cerevisiae and shown that it encodes a second functional pyruvate kinase isoenzyme, Pyk2p. Overexpression of the YOR347c/PYK2 gene on a multicopy vector restored growth on glucose of a yeast pyruvate kinase 1 (pyk1) mutant strain and could completely substitute for the PYK1-encoded enzymatic activity. PYK2 gene expression is subject to glucose repression. A pyk2 deletion mutant had no obvious growth phenotypes under various conditions, but the growth defects of a pyk1 pyk2 double-deletion strain were even more pronounced than those of a pyk1 single-mutation strain. Pyk2p is active without fructose-1,6-bisphosphate. However, overexpression of PYK2 during growth on ethanol did not cause any of the deleterious effects expected from a futile cycling between pyruvate and phosphoenolpyruvate. The results indicate that the PYK2-encoded pyruvate kinase may be used under conditions of very low glycolytic flux.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Allosteric Regulation
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Amino Acid Sequence
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Animals
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Base Sequence
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Ethanol / metabolism
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Fructosediphosphates / metabolism*
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Gene Deletion
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Genes, Fungal
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Genotype
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Glucose / metabolism
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Glycolysis
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Isoenzymes / chemistry
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Isoenzymes / genetics
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Isoenzymes / metabolism
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Kidney / enzymology
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Kinetics
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Liver / enzymology
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Molecular Sequence Data
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Muscle, Skeletal / enzymology
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Oligodeoxyribonucleotides
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Pyruvate Kinase / chemistry
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Pyruvate Kinase / genetics*
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Pyruvate Kinase / metabolism*
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Rats
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Recombinant Fusion Proteins / biosynthesis
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / physiology
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Sequence Homology, Amino Acid
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Substrate Specificity
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beta-Galactosidase / metabolism
Substances
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Fructosediphosphates
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Isoenzymes
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Oligodeoxyribonucleotides
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Recombinant Fusion Proteins
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Ethanol
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Pyruvate Kinase
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beta-Galactosidase
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Glucose
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fructose-1,6-diphosphate