title: Analysis of metabolic and physiological responses to gnd knockout in Escherichia coli by using C-13 tracer experiment and enzyme activity measurement.
abstract: The physiological and metabolic responses to gnd knockout in Escherichia coli K-12 was quantitatively investigated by using the (13)C tracer experiment (GC-MS/NMR) together with the enzyme activity analysis. It was shown that the general response to the gene knockout was the local flux rerouting via Entner-Doudoroff pathway and the direction reversing via non-oxidative pentose phosphate pathway (PPP). The mutant was found to direct higher flux to phosphoglucose isomerase reaction as compared to the wild-type, but the respiratory metabolism was comparable in both strains. The anaplerotic pathway catalyzed by malic enzyme was identified in the mutant, which was accompanied with an up-regulation of phosphoenolpyruvate carboxylase and down-regulation of phosphoenolpyruvate carboxykinase. The presented results provide first evidence that compensatory mechanism existed in PPP and anaplerotic pathway in response to the gnd deletion.
authors.affiliation: Metabolome Unit, Institute for Advanced Biosciences, Keio University, Yamagata 997-0017, Japan.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Jiao
authors.forename: Tomoya
authors.initials: T
authors.lastname: Baba
authors.forename: Hirotada
authors.initials: H
authors.lastname: Mori
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Shimizu
mesh_terms: D002247:Carbon Isotopes; D004798:Enzymes / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008954:Models, Biological; D010427:Pentose Phosphate Pathway / Q000502:physiology; D010734:Phosphogluconate Dehydrogenase / Q000235:genetics*; D011849:Radioactive Tracers
chemical_list: D002247:Carbon Isotopes; D004798:Enzymes; D011849:Radioactive Tracers; D010734:Phosphogluconate Dehydrogenase