title: Study of stationary phase metabolism via isotopomer analysis of amino acids from an isolated protein.
abstract: Microbial production of many commercially important secondary metabolites occurs during stationary phase, and methods to measure metabolic flux during this growth phase would be valuable. Metabolic flux analysis is often based on isotopomer information from proteinogenic amino acids. As such, flux analysis primarily reflects the metabolism pertinent to the growth phase during which most proteins are synthesized. To investigate central metabolism and amino acids synthesis activity during stationary phase, addition of fully (13)C-labeled glucose followed by induction of green fluorescent protein (GFP) expression during stationary phase was used. Our results indicate that Escherichia coli was able to produce new proteins (i.e., GFP) in the stationary phase, and the amino acids in GFP were mostly from degraded proteins synthesized during the exponential growth phase. Among amino acid biosynthetic pathways, only those for serine, alanine, glutamate/glutamine, and aspartate/asparagine had significant activity during the stationary phase.
authors.affiliation: Dept. of Chemical Engineering, University of California, Berkeley, CA 94720, USA.
authors.forename: Afshan S
authors.initials: AS
authors.lastname: Shaikh
authors.forename: Yinjie J
authors.initials: YJ
authors.lastname: Tang
authors.forename: Aindrila
authors.initials: A
authors.lastname: Mukhopadhyay
authors.forename: Héctor García
authors.initials: HG
authors.lastname: Martín
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gin
authors.forename: Peter I
authors.initials: PI
authors.lastname: Benke
authors.forename: Jay D
authors.initials: JD
authors.lastname: Keasling
mesh_terms: D000596:Amino Acids / Q000032:analysis* / Q000096:biosynthesis / Q000378:metabolism*; D002247:Carbon Isotopes; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D007553:Isotope Labeling
chemical_list: D000596:Amino Acids; D002247:Carbon Isotopes; D049452:Green Fluorescent Proteins; D005947:Glucose