PMID:8226637
| Citation |
Chao, YP, Patnaik, R, Roof, WD, Young, RF and Liao, JC (1993) Control of gluconeogenic growth by pps and pck in Escherichia coli. J. Bacteriol. 175:6939-44 |
|---|---|
| Abstract |
It is well-known that Escherichia coli grows more slowly on gluconeogenic carbon sources than on glucose. This phenomenon has been attributed to either energy or monomer limitation. To investigate this problem further, we varied the expression levels of pck, encoding phosphoenolpyruvate carboxykinase (Pck), and pps, encoding phosphoenolpyruvate synthase (Pps). We found that the growth rates of E. coli in minimal medium supplemented with succinate and with pyruvate are limited by the levels of Pck and Pps, respectively. Optimal overexpression of pck or pps increases the unrestricted growth rates on succinate and on pyruvate, respectively, to the same level attained by the wild-type growth rate on glycerol. Since Pps is needed to supply precursors for biosyntheses, we conclude that E. coli growing on pyruvate is limited by monomer supply. However, because pck is required both for biosyntheses and catabolism for cells growing on succinate, it is possible that growth on succinate is limited by both monomer and energy supplies. The growth yield with respect to oxygen remains approximately constant, even though the overproduction of these enzymes enhances gluconeogenic growth. It appears that the constant yield for oxygen is characteristic of efficient growth on a particular substrate and that the yield is already optimal for wild-type strains. Further increases in either Pck or Pps above the optimal levels become growth inhibitory, and the growth yield for oxygen is reduced, indicating less efficient growth. |
| Links | |
| Keywords |
Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli/growth & development; Gene Expression; Genes, Bacterial; Gluconeogenesis/genetics; Kinetics; Oxygen Consumption; Phosphoenolpyruvate Carboxykinase (GTP)/biosynthesis; Phosphoenolpyruvate Carboxykinase (GTP)/genetics; Phosphoenolpyruvate Carboxykinase (GTP)/metabolism; Phosphotransferases (Paired Acceptors)/biosynthesis; Phosphotransferases (Paired Acceptors)/genetics; Phosphotransferases (Paired Acceptors)/metabolism; Plasmids; Pyruvates/metabolism; Succinates/metabolism |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.